�����Ƶ

Rebecca Davis Gibbons and Stephen Herzog
 

Introduction

The dangers of nuclear weapons have recaptured the global imagination. When Russian President Vladimir Putin launched his full-scale invasion of Ukraine in February 2022, he alluded to potential nuclear strikes against would-be intervenors.1 Putin threatened anyone who opposed Russian actions with consequences “never seen in your history.”2 Moscow has followed up with dozens of nuclear signals during the conflict—both threats and escalatory actions.3 The North Atlantic Treaty Organization (NATO) has supplied Ukraine with weapons but so far has avoided direct involvement in the conflict. Meanwhile, relentless media coverage of nuclear risks has reacquainted the global public with the dilemmas of the atomic age.4 The world’s most powerful weapons are now front and center in international politics, affecting everything from nuclear counterproliferation prospects to risk reduction initiatives.5

Yet, just one year before Russia attacked Ukraine, a new multilateral nuclear disarmament treaty entered into force. The Treaty on the Prohibition of Nuclear Weapons (TPNW), popularly known as the Nuclear Ban, achieved this legal standing after its ratification by fifty states. The agreement prohibits nuclear weapons and all related production and military activities, thereby posing a challenge to existing military doctrines of nuclear deterrence.6 Among the explicitly outlawed activities are nuclear threats like those issued by the Kremlin. But the TPNW carries the weight of international law only for its sixty-nine states parties.7 All nuclear-armed countries, as well as those relying on extended nuclear deterrence, have rejected the treaty and argue that they are not bound by its provisions.8

This lack of support from states that depend on nuclear weapons has done little to dampen the enthusiasm of Nuclear Ban proponents. In June 2022, TPNW members, observer states, and antinuclear activists held the treaty’s First Meeting of States Parties in Vienna, Austria. They took action on various aspects of treaty implementation, including steps to develop verification protocols and fulfill the accord’s positive obligations of victim assistance and environmental remediation.9 The Vienna meeting ended with the adoption of a forward-looking declaration by the states parties. It commits the TPNW membership to “harness the public conscience in support of our goal of universal adherence to the Treaty and its full implementation.”10

For many states and members of the public, the war in Ukraine has emphasized a growing imperative for nuclear disarmament. The risks of nuclear confrontation between Russia and NATO have received considerable media and public attention. Additionally, the Kremlin’s use of nuclear threats to enable its invasion of a sovereign state may herald an unsettling new revisionist era of nuclear politics. It is not difficult to interpret these dynamics as an unambiguous reminder of the dangers of living in a world where nine states possess some 12,500 nuclear weapons.11 Disarmament sentiments accordingly surrounded the May 2023 Group of 7 Summit in Hiroshima, Japan, where the legacy of the atomic bomb looms large.

Some governments seem to have drawn the exact opposite lesson, however. Finland and Sweden responded to the war by moving away from their long-standing neutrality and seeking to join NATO—an explicitly nuclear alliance.12 In Seoul, policymakers drew parallels between the North Korean threat and Russia’s invasion of Ukraine.13 South Korean President Yoon Suk Yeol even briefly advocated for indigenous proliferation, leading to increased nuclear deterrence coordination with the United States.14 To leaders from many countries facing powerful adversaries and threats to their national survival, the lesson of the Ukraine war is to rely more, not less, on nuclear deterrence.

Given these trends, we provide an assessment of how Russia’s war on Ukraine may affect the prospects of the TPNW. Our analysis covers relevant predictions from the scholarly literature, the current trajectory of state positions on nuclear arms, implications for public opinion, and a discussion of how the use of nuclear weapons may change the international climate. We reach two central conclusions about the Nuclear Ban’s approach to nuclear disarmament. Both have wide-ranging implications for the future of the global nuclear order.

First, the nuclear overtones of the war in Ukraine have increasingly polarized backers of the policies of disarmament and deterrence. Likewise, the public debate—seen as central to repudiating the legitimacy of possessing nuclear arms—remains unsettled.15 Disarmament will have relatively little near-term appeal for states relying on their own nuclear arsenals or on extended nuclear deterrence. TPNW member states and antinuclear advocates, however, are likely to use the coming years to institutionally develop the treaty and further stigmatize the bomb.

Recent events have strengthened the Nuclear Ban proponents’ disarmament narrative. The seriousness of Putin’s threats may well frighten younger generations with no memories of the Cuban missile crisis or duck-and-cover drills. In the past, nuclear fears dealt primarily with the idea of a nuclear “sword” that could be used in devastating attacks. But Russia has also used nuclear arms as a “shield” to deter external intervention in its conventional war on Ukraine. Moscow’s nuclear arsenal has enabled mass casualties and human suffering both on the battlefield and among the Ukrainian civilian population in Bucha, Mariupol, and beyond.

Second, emerging great-power competition among the United States, China, and Russia is a significant setback to nuclear disarmament efforts premised on phased reductions of bilateral U.S.-Russian arms control.16 It calls into question these states’ dedication to the disarmament pledge entailed in Article 6 of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). These traditional arms control and disarmament approaches faced hurdles before February 2022, but they seem even less viable at the moment. Russia’s suspension of the New Strategic Arms Reduction Treaty (New START) in February 2023 is illustrative, as is China’s ongoing expansion of its nuclear arsenal.17 Flagging progress toward eliminating nuclear weapons has led disarmament to become the main alternative nuclear narrative to the status quo. Now, the nuclear dynamics of Putin’s war are highlighting the very injustices that Nuclear Ban proponents critique.18

If any doubts remained about the TPNW’s staying power, the war in Ukraine helped erase them. Equipped with compelling new evidence of nuclear dangers and increased nuclear salience, Nuclear Ban advocates have moved to consolidate the treaty as a fixture of the global nuclear order. As interest in nuclear disarmament grows, the TPNW has risen as the most prominent instrument for achieving this objective. Continued avoidance of the TPNW could carry risks for the great powers’ credibility on nuclear nonproliferation and disarmament, their relationships with the Global South, and the continuity of their military alliances.
 

Endnotes

• 1Alexander K. Bollfrass and Stephen Herzog, “,” Survival 64 (4) (2022): 7, 19–20.
• 2Ibid., 7.
• 3Liviu Horovitz and Anna Clara Arndt, “,” SWP Research Division International Security, Working Paper no. 1, February 2023.
• 4See, for example, one very impactful media event: the movement of the Doomsday Clock to ninety seconds to midnight by the Bulletin of the Atomic Scientists. Science and Security Board, “,” Bulletin of the Atomic Scientists, January 24, 2023.
• 5See the essays by Wilfred Wan and Doreen Horschig in this publication: Wilfred Wan, “Wither Nuclear Risk Reduction?” and Doreen Horschig, “A Turn to Nuclear Counterproliferation: Consequences of a Deteriorating Nonproliferation Regime,” in Rebecca Davis Gibbons, Stephen Herzog, Wilfred Wan, and Doreen Horschig, The Altered Nuclear Order in the Wake of the Russia-Ukraine War (Cambridge, Mass.: American �����Ƶ of Arts and Sciences, 2023).
• 6For the text of the agreement, see , UN Doc A/CONF.229/2017/8, July 7, 2017. See also Jonathan L. Black-Branch, (Cambridge: Cambridge University Press, 2021).
• 7Carlos Iván Fuentes and Santiago Villalpando, “,” in The Oxford Guide to Treaties, 2nd ed., ed. Duncan B. Hollis (Oxford: Oxford University Press, 2021), 225. For the list of the sixty-nine ratifying states parties and ninety-three states signatories to the TPNW, see United Nations, Office for Disarmament Affairs (UNODA), “” (accessed October 3, 2023).
• 8Nick Ritchie and Ambassador Alexander Kmentt, “,” Journal for Peace and Nuclear Disarmament 4 (1) (2021): 70–93.
• 9Rebecca Davis Gibbons and Stephen Herzog, “,” Arms Control Today 52 (7) (2022): 12–17.
• 10“,” TPNW/MSP/2022/CRP.8, June 23, 2022.
• 11Hans M. Kristensen, Matt Korda, Eliana Reynolds, and Kate Kohn, “,” Federation of American Scientists, March 31, 2023.
• 12William Alberque and Benjamin Schreer, “,” Survival 64 (3) (2022): 67–72.
• 13Choe Sang-Hun, “,” The New York Times, April 6, 2022; and Wooyeal Paik, “,” Institute for Security and Development Policy, Issue Brief, May 5, 2023.
• 14Stephen Herzog and Lauren Sukin, “,” Carnegie Endowment for International Peace, January 25, 2023; and Kelsey Davenport, “,” Arms Control Today 53 (4) (2023): 25–26.
• 15Rebecca Davis Gibbons, “,” The Nonproliferation Review 25 (1–2) (2018): 35; and Motoko Mekata, “,” Journal for Peace and Nuclear Disarmament 1 (1) (2018): 89–90.
• 16Rebecca Davis Gibbons and Stephen Herzog, “,” Contemporary Security Policy 43 (1) (2022): 69–73.
• 17Shannon Bugos, “,” Arms Control Today 53 (2) (2023): 24–25; and Shannon Bugos, “,” Arms Control Today 51 (10) (2021): 26–28.
• 18Franziska Stärk and Ulrich Kühn, “,” Bulletin of the Atomic Scientists, October 26, 2022.

More Nuclear Proliferation or More Nuclear Disarmament?

An increase in the number of nuclear-armed powers would be antithetical to the aims of the TPNW and its global prohibition on the bomb. But since February 2022, many pundits and politicians have argued that Russia’s actions will incentivize nuclear proliferation among nonnuclear-armed states.19 The basis of this claim is that Russia invaded a sovereign nation, Ukraine, which, in exchange for assurances about its territorial integrity, gave up the nuclear weapons it inherited when the Soviet Union broke apart.20 Perhaps, the logic goes, if Ukraine had retained those weapons, it could have deterred Russia’s attack.21 Former U.S. President Bill Clinton even appeared to back this notion in April 2023 by expressing regret for pushing Ukraine to disarm.22

If one endorses this thinking, clear implications for global nuclear proliferation and disarmament emerge. For instance, former U.S. Ambassador to Ukraine Steven Pifer highlights the potential precedents created by Russian actions: “What Russia (which has the world’s largest nuclear arsenal) has done to Ukraine (a country that gave up its arsenal) likely will rank high in the mind of those in future countries who consider whether to acquire, or to give up, nuclear weapons.”23 Michael O’Hanlon and Bruce Riedel take a similar tack: “If you have nuclear weapons, keep them. If you don’t have them yet, get them, especially if you lack a strong defender like the United States as your ally, and if you have a beef with a big country that could plausibly lead to war.”24 Commentaries like these have become so ubiquitous in elite circles in places like Washington and Brussels that their lessons seem to be treated as “fact” in many ongoing policy discussions.

Consequently, fears of moral hazard have also arisen. U.S. Secretary of Defense Lloyd Austin has gone so far as to suggest that additional states will seek to proliferate so they may engage in aggression while under the protection of nuclear deterrence. In a November 2022 speech, Austin argued that leaders in other countries “could well conclude that getting nuclear weapons would give them a hunting license of their own.”25 If the Ukraine crisis indeed spurred additional cases of nuclear proliferation, it would be a considerable blow to the TPNW.

This would be the case regardless of whether countries acquired nuclear weapons with the intent to use them or for the purposes of deterrence. The Nuclear Ban’s prohibitions are motivated, in part, by the devastating humanitarian and environmental consequences of nuclear use. For example, the International Committee of the Red Cross warns that humanitarian agencies lack the capacity to address casualties from blast, thermal wave, radiation, and radioactive fallout following a nuclear detonation.26 Champions of the Nuclear Ban also reject nuclear deterrence as a dangerous and immoral source of security. They argue that leaders do not always act rationally, which is a key condition for successful deterrence strategy, and that the high nuclear readiness and alert levels required for credible deterrence imperil the world.27 Nuclear Ban advocates also point to the many accidents involving nuclear weapons and the consequences of 2,056 nuclear explosive tests that have taken place over the decades.28 To many TPNW proponents, the avoidance of nuclear disaster throughout the Cold War was the product of luck, not the careful and rational execution of deterrence.29 Nuclear proliferation would thus pose major setbacks to the Nuclear Ban agenda.

Reactionary policy takes are a normal and expected part of every major international event. Nuclear proliferation would have considerable consequences for global security, U.S. alliances, and the future of nuclear nonproliferation and disarmament. Reflecting on some of the assumptions of these prognostications can therefore be a useful exercise. Before weighing the evidence from the Ukraine war, we explore whether practitioner predictions align with systematic academic research on nuclear proliferation. Overall, we find some reasons to be skeptical and are relatively more optimistic about nuclear forbearance and the prospects for the TPNW.

At first glance, those expecting additional proliferation in light of the war in Ukraine may appear to be correct. The dominant theories explaining nuclear proliferation focus on the demand side of the equation due to security concerns. These theories predict that states seek nuclear weapons to deter serious security threats: adversaries with superior conventional forces or nuclear weapons.30 States may observe Russia’s ongoing aggression and consider the deterrent value of having the bomb. Problematically, a cascade or domino theory of nuclear proliferation predicts that proliferation begets proliferation. Research indicates that nuclear dominoes are not merely a myth, although states reacting to an adversary’s proliferation do not always complete their journey to nuclearization. For example, Nicholas Miller finds that China’s first nuclear test explosion in 1964 led leaders to ponder the bomb in Australia, India, Indonesia, Japan, and Taiwan. Only India eventually became a nuclear-armed state.31

More than thirty states have explored building a nuclear weapons program during the nuclear age. Yet, only ten states have developed indigenous nuclear weapons.32 Scholarly research explains this outcome in several ways. We unpack four of the—not always mutually exclusive—main reasons below, showing their relevance to nuclear reactions to the war in Ukraine and the future of the Nuclear Ban.
 

The Role of Alliances with Nuclear-Armed States
 

One alternative to building an indigenous nuclear program is to rely on extended nuclear deterrence. During the Cold War, the United States created a system of alliances to deter the Soviet Union, but these alliances also served U.S. nonproliferation goals.33 The view was that American protégés would not need an independent nuclear arsenal if they had credible U.S. protection. Based on large-N statistical analysis, Philipp Bleek and Eric Lorber find that states receiving security guarantees from a nuclear-armed patron are less likely to explore, pursue, or acquire their own nuclear deterrent.34 Moreover, Alexandre Debs and Nuno Monteiro employ detailed qualitative and game-theoretical evidence to demonstrate that states will be willing to pursue the bomb only if they lack a reliable nuclear ally.35 Eric Brewer, Nicholas Miller, and Tristan Volpe thus conclude, “countries with allied protection are less vulnerable to external aggression than Ukraine and therefore less likely to feel compelled to seek a nuclear deterrent.”36 Of course, rising security challenges may lead to doubts about the credibility of such guarantees, requiring further assurances from the United States. But relying on the so-called nuclear umbrella is directly at odds with the TPNW’s prohibitions. States that turn to extended nuclear deterrence to counter threats from Russia and beyond are a challenge to the Nuclear Ban.37
 

U.S. Efforts to Prevent Nuclear Proliferation
 

Extended deterrence is just one of several tools used by the United States to prevent the emergence of new nuclear weapon states. Since the 1960s, Washington has promoted several “strategies of inhibition,” including sanctions, treaties, diplomacy, and coercion.38 These efforts will also serve to dampen proliferation pressures stemming from Russia’s war on Ukraine. For instance, Miller finds that states vulnerable to U.S. sanctions are less likely to proliferate.39 Another economic argument is offered by Etel Solingen, who posits that governments seeking integration within the global economy will reject nuclear weapons.40 In Solingen’s book, the case studies of economic integration deal with becoming part of the U.S.-led liberal economic order, so the theory is predicated upon U.S. leadership.41

The United States has long been at the forefront of promoting the nonproliferation regime. Rebecca Davis Gibbons argues that almost all U.S. presidential administrations since Lyndon B. Johnson’s have exerted considerable diplomatic effort in universalizing the NPT and promoting nuclear safeguards.42 Washington has also led the development of adaptations to the nonproliferation regime when weaknesses in the institutional framework became apparent. These and other scholarly works indicate that the United States will work to stop future proliferation, whether it is motivated by the war in Ukraine or not. Emerging multipolarity and tension among the United States, Russia, and China may make U.S. nonproliferation efforts more difficult over time.43 Nonetheless, for the foreseeable future, the United States will retain many of the nonproliferation tools it has used historically.

U.S. leadership in the nonproliferation regime may mean less proliferation, but it is unlikely to be good news for proponents of the Nuclear Ban agenda. If Russia’s war brings countries deeper into the American fold, Washington will have greater leverage over them. The United States objects to the TPNW and has a track record of pressuring its allies to refrain from joining the agreement.44
 

Managerial Challenges of Building Nuclear Weapons
 

The challenge of building an indigenous nuclear weapons program is also an impediment to proliferation in response to Russia’s invasion of Ukraine. In detailed case studies of Iraq’s and Libya’s pursuit of nuclear weapons, Målfrid Braut-Hegghammer illustrates how weak state capacity can hamper progress toward the ultimate weapon.45 Similarly, Alexander Montgomery finds that even when states are able to secure sensitive nuclear assistance, they are often unable to successfully translate this help into acquiring the bomb.46 Brewer, Miller, and Volpe note other obstacles to finalizing a nuclear program, including military attacks by adversary states and various types of sabotage.47 All of these dynamics would be at play in a proliferation attempt.

Another nuclear development stumbling block is the vast system of intrusive International Atomic Energy Agency (IAEA) safeguards. These verification measures, pursuant to Article 3 of the NPT, have significantly increased the ability of the international community to both detect and deter nuclear proliferation.48 Fear of preventive strikes and punishment from nuclear suppliers and the broader international community may thus encourage states to be satisfied with nuclear latency—the ability to develop nuclear arms without having crossed the proliferation threshold. A growing number of scholars suggest that such latency short of the bomb may have some deterrent and compellent benefits.49 Even if states opt for latency over proliferation, however, this is no guarantee that they will be willing to embrace the TPNW.
 

Strong Norms against Nuclear Weapons Development and Use
 

The scholarly literature offers a modicum of optimism for the future of the TPNW. The increased salience of nuclear dangers due to Russian nuclear saber-rattling may draw attention to normative reasons for states to reject nuclear weapons and join the TPNW. Maria Rost Rublee shows that international crises have contributed to creating normative environments that affect state decisions about nuclear weapons. She argues that the success of the nonproliferation regime must be understood as an outcome of socialization wherein states feel pressure not to go nuclear.50 Matthew Fuhrmann and Xiaojun Li find that norm diffusion brings states into regional nuclear-weapon-free-zone (NWFZ) agreements. If the nuclear dynamics of the war convince more states in a region to accede to the TPNW, their neighbors may be more likely to join as well. Fuhrmann and Li’s analysis seems to hold only in regions without significant militarized disputes, however. This shows the predominance of security considerations in decision-making about nuclear treaties.51 Similarly, Espen Mathy suggests that states facing regional normative pressure are more likely to join the TPNW, but only in places where the Nuclear Ban is not perceived to weaken national security.52 Mathy’s argument corresponds with those of Stephen Herzog, who demonstrates the centrality of security considerations in many NPT and Comprehensive Nuclear-Test-Ban Treaty (CTBT) ratifications.53

How are nonnuclear norms faring today? As Nina Tannenwald explains in the context of the Ukrainian conflict, the nuclear taboo, “while widely shared, is more fragile than other kinds of norms because a small number of violations would likely destroy it.”54 Tannenwald also describes the taboo as a prohibition on being the first to use nuclear weapons, which therefore faces challenges from Putin’s threats.55 Still, nuclear weapons have not been used, and the norm remains unbroken. Countries are not rushing to withdraw from the NPT, a treaty that scholars have shown to be durable even when it has been challenged by contentious world events.56 The norms of nonproliferation and the nuclear taboo are also both promoted and strengthened by the states that have joined the TPNW. And the extant scholarly research indicates numerous opportunities for the propagation of antinuclear norms to states that do not face serious security threats. Even if nuclear proliferation appears under control at the moment, that distinction is worthy of note. The scholarly literature predicts a sharp division between states that will rely on nuclear benefactors and those that may opt for the TPNW.57

In sum, many factors push against nuclear acquisition, despite the fact that a nonnuclear state has been the victim of a nuclear-armed state’s aggression. As Robert Einhorn cautions when commenting on the flurry of Ukraine war–induced proliferation predictions, “nuclear proliferation does not occur in theory. It occurs in particular countries, with particular security situations and adversaries, security relationships with friendly states, national priorities, technological and financial capabilities, and domestic balances of political power.”58 The scholarly literature about the causes of nuclear proliferation and restraint suggests that a cascade of proliferation is unlikely in the coming years. Many states may even be motivated for normative reasons to reject nuclear weapons and, potentially, to join the TPNW. These points notwithstanding, the relevant scholarship predicts a growing schism between those states that embrace disarmament on normative grounds and those that view nuclear weapons and deterrence as vital to their national security.

Russia’s war on Ukraine will have heterogeneous effects around the world. Opponents of the bomb will see the nuclear dynamics of the conflict as the epitome of the problems of the atomic age. The war will reinforce their arguments favoring nuclear disarmament. For those who perceive security benefits from these weapons, the war will cause them to rely more on nuclear deterrence. Reconciling these views promises to be a significant, if not the utmost, challenge to the future of the global nuclear order.
 

Endnotes

• 19For a prominent exception, see Robert Einhorn, “” Arms Control Today 52 (8) (2022): 6–12.
• 20Mariana Budjeryn, (Baltimore: Johns Hopkins University Press, 2022).
• 21During the early 1990s, some observers called for Ukraine to maintain possession of these nuclear weapons for deterrence purposes. See, for example, John J. Mearsheimer, “,” Foreign Affairs 72 (3) (1993): 50–66. For the counterargument at the time, see, for example, Steven E. Miller, “,” Foreign Affairs 72 (3) (1993): 67–80. And for a discussion of the problematic nature of the facts and logic underlying arguments in support of a Ukrainian nuclear arsenal, particularly dealing with command and control of the weapons, see, for example, Maria Rost Rublee, “,” Survival 57 (2) (2015): 145–156.
• 22Ellie Cook, “,” Newsweek, April 5, 2023.
• 23Steven Pifer, “,” Bulletin of the Atomic Scientists, June 1, 2022.
• 24Michael E. O’Hanlon and Bruce Riedel, “,” Order from Chaos [blog], Brookings Institution, March 29, 2022.
• 25Jim Garamone, “,” DoD News, November 19, 2022.
• 26International Committee of the Red Cross, “,” August 29, 2020.
• 27See, for example, International Campaign to Abolish Nuclear Weapons (ICAN), “” (accessed October 3, 2023).
• 28Scott D. Sagan, (Princeton, N.J.: Princeton University Press, 1995); Eric Schlosser, Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety (London: Penguin, 2013); and Patricia Lewis, Heather Williams, Benoît Pelopidas, and Sasan Aghlani, “,” Chatham House Report, April 28, 2014. See also Daryl G. Kimball, “,” Arms Control Today 49 (7) (2019): 3.
• 29Benoît Pelopidas, “,” European Journal of International Security 2 (2) (2017): 240–262.
• 30Scott D. Sagan, “,” International Security 21 (3) (1996–1997): 57–58.
• 31Nicholas L. Miller, “” Security Studies 23 (1) (2014): 33–73.
• 32Today, nine states are nuclear-armed: Britain, China, France, India, Israel, North Korea, Pakistan, Russia, and the United States. South Africa built a small nuclear arsenal but dismantled it as part of the transition away from the segregationist apartheid system. See, for example, Philipp C. Bleek, “,” Harvard University Project on Managing the Atom and James Martin Center for Nonproliferation Studies, discussion paper, June 2017.
• 33Francis J. Gavin, “,” International Security 40 (1) (2015): 42–43.
• 34Philipp C. Bleek and Eric B. Lorber, “,” Journal of Conflict Resolution 58 (3) (2014): 438. For an alternative perspective arguing that overly credible security guarantees may actually lead to fears of entrapment and, ironically, spur interest in proliferation, see Lauren Sukin, “,” Journal of Conflict Resolution 64 (4) (2020): 1011–1042.
• 35Alexandre Debs and Nuno P. Monteiro, (Cambridge: Cambridge University Press, 2017). See also Alexander Lanoszka, (Ithaca, N.Y.: Cornell University Press, 2018).
• 36Eric Brewer, Nicholas L. Miller, and Tristan Volpe, “,” Foreign Affairs, November 17, 2022.
• 37Some Nuclear Ban proponents argue that states could join the TPNW and still remain NATO members. Such states would need to withdraw entirely from NATO’s Nuclear Planning Group and could not have nuclear weapons stationed on their soil. See International Campaign to Abolish Nuclear Weapons, “,” December 2020.
• 38Gavin, “Strategies of Inhibition.”
• 39Nicholas L. Miller, “,” International Organization 68 (4) (2014): 913–944; and Nicholas L. Miller, (Ithaca, N.Y.: Cornell University Press, 2018).
• 40Etel Solingen, “,” International Security 19 (2) (1994): 126–169; and Etel Solingen, (Princeton, N.J.: Princeton University Press, 2007).
• 41Rebecca Davis Gibbons, (Ithaca, N.Y.: Cornell University Press, 2022), 32.
• 42Ibid. Gibbons notes, however, that exceptions can occur when other strategic goals take priority over nuclear nonproliferation. See, for example, ibid., 27–28. See also Jonathan R. Hunt, (Stanford, Calif.: Stanford University Press, 2022); and Jeffrey M. Kaplow, (Cambridge: Cambridge University Press, 2023).
• 43See, for example, Gibbons and Herzog, “Durable Institution under Fire?”
• 44See, for example, Stuart Casey-Maslen, (Oxford: Oxford University Press, 2019), 52.
• 45Målfrid Braut-Hegghammer, (Ithaca, N.Y.: Cornell University Press, 2016). For a discussion of how regime structure can be an obstacle to proliferation, see, for example, Jacques E.C. Hymans, (Cambridge: Cambridge University Press, 2012).
• 46Alexander H. Montgomery, “,” in The Nuclear Renaissance and International Security, ed. Adam N. Stulberg and Matthew Fuhrmann (Stanford, Calif.: Stanford University Press, 2013), 177–202.
• 47Brewer, Miller, and Volpe, “Ukraine Won’t Ignite a Nuclear Scramble.”
• 48Harald Müller and Andreas Schmidt, “,” in Forecasting Nuclear Proliferation in the 21st Century: The Role of Theory, ed. William C. Potter and Gaukhar Mukhatzhanova (Stanford, Calif.: Stanford University Press, 2010), 124–158; Allison Carnegie and Austin Carson, “,” American Journal of Political Science 63 (2) (2019): 269–285; and Rebecca Davis Gibbons and Todd Robinson, “,” The Nonproliferation Review, May 30, 2022.
• 49Matthew Fuhrmann, “Influence without Bombs: The Logic of Latent Nuclear Deterrence” (unpublished working paper, 2019); Stephen Herzog, “,’�ĝ Journal for Peace and Nuclear Disarmament 3 (1) (2020): 60–86; and Tristan A. Volpe, (Oxford: Oxford University Press, 2023).
• 50Maria Rost Rublee, (Athens, Ga.: University of Georgia Press, 2009).
• 51Matthew Fuhrmann and Xiaojun Li, “” (unpublished working paper, August 14, 2009).
• 52Espen Mathy, “” The Nonproliferation Review, April 17, 2023. For a discussion of regional (non)proliferation dynamics, see, for example, Wilfred Wan, (Athens, Ga.: University of Georgia Press, 2008).
• 53Stephen Herzog, “” (Ph.D. diss., Yale University, 2021).
• 54Nina Tannenwald, “” Foreign Policy, July 1, 2022.
• 55Nina Tannenwald, “The Great Unraveling: The Future of the Nuclear Normative Order,” in Nina Tannenwald and James M. Acton, Meeting the Challenges of the New Nuclear Age: Emerging Risks and Declining Norms in the Age of Technological Innovation and Changing Nuclear Doctrines (Cambridge, Mass.: American �����Ƶ of Arts and Sciences, 2018).
• 56Liviu Horovitz, “,” Journal of Strategic Studies 38 (1–2) (2015): 126–158; Miriam Barnum and James Lo, “,” Journal of Peace Research 57 (6) (2020): 740–751; Michal Smetana and Joseph O’Mahoney, “,” Contemporary Security Policy 43 (1) (2022): 24–49; and Sanne Cornelia J. Verschuren, “,” in Routledge Handbook of the Future of Warfare, ed. Artur Gruszczak and Sebastian Kaempf (London: Routledge, 2023), 400–410.
• 57Harald Müller and Carmen Wunderlich, “,” ��æ�岹���ܲ� 149 (2) (2020): 171–189; Nina Tannenwald, “,” in Non-Nuclear Peace: Beyond the Nuclear Ban Treaty, ed. Tom Sauer, Jorg Kustermans, and Barbara Segaert (Cham, Switzerland: Palgrave Macmillan, 2020), 115–129; Naomi Egel and Steven Ward, “,” European Journal of International Relations 28 (4) (2022): 751–776; and Stephen Herzog, “,” Science 378 (6616): 115.
• 58Einhorn, “Will Russia’s War on Ukraine Spur Nuclear Proliferation?” 6.

State-Level Evidence

Relevant scholarly and policy literature predicts that events like Russia’s war on Ukraine will polarize countries around the globe, but what does the evidence actually say? Are states moving toward the deterrence or the disarmament camp? Here, we explore how states have approached the TPNW politically since February 2022. The picture appears to be much more indeterminate than a simple story of polarization. In fact, two main narratives about nuclear weapons have risen to the fore. How governments will react to them will likely depend on the evolution of the nuclear dynamics of the war. This presents both challenges and opportunities for the Nuclear Ban.

The first narrative points to the unique set of dangers presented by wars involving nuclear-armed states. According to the latest open-source estimates, Russia has a stockpile of 5,889 warheads, many of which are orders of magnitude more powerful than those that were dropped on Hiroshima and Nagasaki in 1945. These weapons include nearly two thousand tactical nuclear weapons intended for battlefield use.59 And in June 2023, Putin confirmed that Russia had begun to forward-deploy such tactical nuclear weapons in Belarus, which borders Ukraine.60 Repeated nuclear threats from Putin and other Russian officials raise the specter that the long-standing taboo on using these weapons will be shattered. Perhaps even scarier, Russia’s deterrent threats directed at preventing NATO intervention in Ukraine show that nuclear weapons can be employed as a tool to challenge the sovereignty of nonnuclear states. Ukraine’s very survival as a state is in jeopardy. 61

The scariest possibility is that of a strategic nuclear exchange. Ukraine borders NATO territory, and the main backers of the government in Kyiv are member countries of the Atlantic Alliance. The three NATO nuclear powers—Britain, France, and the United States—have a combined 5,759 nuclear weapons, virtual parity with Moscow.62 The United States also deploys approximately one hundred tactical nuclear weapons in five NATO countries: Belgium, Germany, Italy, the Netherlands, and Turkey.63 Unclear redlines, potential misperceptions, and accidental spillover all pose risks of escalation to a civilization-threatening nuclear war.64 While the chances of nuclear use and nuclear war still seem quite low, such odds have increased considerably due to the war in Ukraine. The threats that nuclear arms pose to sovereignty and humanity thus form the basis of a nuclear narrative that favors the TPNW and its approach to banning the bomb. In theory, the prevalence of this narrative should serve as a check against additional nuclear proliferation and result in the diffusion of pro-disarmament norms.

The second narrative acknowledges the inherent dangers of nuclear weapons but concludes that this is precisely why greater reliance on nuclear deterrence is needed. Ukraine was invaded by Russia, which had joined with Britain and the United States to offer Kyiv security assurances in the 1994 Budapest Memorandum. The three states did so in exchange for Ukraine transferring to Russia the world’s third-largest nuclear arsenal—inherited when the Soviet Union collapsed—and joining the NPT as a nonnuclear state. Though Ukraine did not have operational control of the weapons, it could have leveraged its technology inheritance and know-how to develop an arsenal.65 Few, if any, observers think that Moscow would have attacked a nuclear-armed Ukraine that could have retaliated with strikes against Russian population centers and strategic military targets. One resultant reading of Ukraine’s history is that nuclear disarmament is unwise because it makes a state vulnerable to invasion.66 This interpretation of events is hardly sympathetic to the arguments of the Nuclear Ban activists and for TPNW membership. It calls for greater reliance on nuclear weapons to protect national sovereignty and survival.

Ukraine also lacked nuclear security guarantees like those of the NATO countries and others under the U.S. nuclear umbrella. Russian forces have occupied territory in both Ukraine and Georgia, purportedly over ethno­politics disagreements. But in the case of a similar dispute with Estonia, covered by NATO’s Article 5 mutual defense pledge, the Kremlin resorted to plausibly deniable cyberattacks.67 Moscow has also engaged in campaigns of influence, election interference, and espionage against other NATO states. The point remains, however, that Russia seems much more willing to overtly attack states that do not have formal nuclear security guarantees. After all, such assurances are believed to be demonstrations of resolve by the United States to defend its protégés.68 The second narrative would therefore call for a rejection of the TPNW, either in favor of indigenous proliferation or further dependence on extended nuclear deterrence.

Whether states are proponents of disarmament or deterrence, Russia’s attack on Ukraine will affect perceptions of security assurances issued by nuclear-armed states. The contravention of the Budapest Memorandum would seem to undermine future Russian pledges to partners, who will certainly want stronger legal agreements. Whether such doubts will extend to other security guarantors, like the United States, is not clear. But, as Francesca Giovannini writes, the war in Ukraine shows that “a patchy regime of negative security assurances [is] . . . profoundly inadequate to provide the kind of reassurances that non-nuclear-weapon states might require in a highly unpredictable global nuclear order.”69 Russian actions and broader concerns about the responsibility of nuclear-armed NPT states could lead to calls for stronger and more universal security guarantees.

By and large, states from the Global South have found the first narrative about nuclear dangers and disarmament imperatives to be more compelling than the second narrative about deterrence. This position, however, is not a new development. Scholars such as Benoît Pelopidas have also written about why it is unsound to assume, a priori, a universal desire for nuclear weapons among states.70 States from Latin America and the Caribbean signed the Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (Treaty of Tlatelolco) in 1967, establishing the world’s first NWFZ partly in response to the grave fears that accompanied the Cuban missile crisis.71 Since then, other states in the Global South have contributed to the development of these zones in Africa, Central Asia, the South Pacific, and Southeast Asia. Many of these nonnuclear states without nuclear security assurances spearheaded the negotiation of the TPNW in 2017.72 Today, states from the Global South form the majority of the treaty’s membership base.

At the first TPNW Meeting of States Parties in 2022, the nuclear dynamics of the war in Ukraine confirmed the disarmament views of numerous governments. United Nations (UN) Secretary General António Guterres opened the Vienna meeting with a video address capturing these sentiments, stating, “We must stop knocking on doomsday’s door” and “Let’s eliminate these weapons before they eliminate us.”73 The treaty members proceeded to discuss timelines for eliminating weapons, plans for universalizing the agreement, and ways to compensate victims of nuclear attacks and nuclear explosive tests.

However, the meeting’s attendees offered no explicit condemnation of Russia by name for its nuclear threats. The meeting’s Vienna Declaration instead states, “We are alarmed and dismayed by threats to use nuclear weapons and increasingly strident nuclear rhetoric. We stress that any use or threat of use of nuclear weapons is a violation of international law, including the Charter of the United Nations. We condemn unequivocally any and all nuclear threats, whether they be explicit or implicit and irrespective of the circumstances.”74  This portion of the statement—and, specifically, whether to single out Russia—was hotly debated. Many of the delegations in Vienna objected because they viewed Russia’s behavior as part and parcel of relying on nuclear deterrence. To them, Moscow’s actions were simply further evidence of a long history of nuclear threats and misbehavior by great powers.75 A more cynical interpretation is that states from the Global South were not keen to criticize Russia and suffer future economic or political repercussions.76 Scholars have also argued that some states in the Global South have long chosen not to condemn Russian actions as a way of protesting decades of perceived Western hypocrisy in upholding the rules of the liberal international order.77

One metric that can help to gauge the strength of the disarmament narrative is membership in the TPNW. The treaty opened for signature in 2017, and only nine of the sixty-nine ratifying parties and seven of the ninety-three state signatories took those actions after Russia launched its full-scale invasion of Ukraine in February 2022.78 So far, the war does not seem to be resulting in significant new membership for the Nuclear Ban, perhaps due to security concerns created by Russia’s actions.79 But this fact may also indicate that most states without significant domestic debates about TPNW accession have already joined the treaty.80 States that have not joined either reject the treaty or face a more difficult decision process, due either to national considerations or international pressures.

The growing divide between proponents of disarmament and deterrence predicted by the literature was evident in Vienna. Security concerns were paramount in the statements made by several nuclear umbrella states that were observers to the proceedings.81 Their sentiments aligned with the second narrative about an increasing need to rely on nuclear deterrence. The representative of Norway, a country that has been at the forefront of the movement to draw attention to the humanitarian impacts of nuclear weapons, stated that “Russia’s rhetoric on nuclear weapons is reckless and dangerous.” Yet, for Oslo, “signing the TPNW . . . would be incompatible with our NATO obligations.”82 Meanwhile, the German representative noted that his country faced a hostile Russia and would thus not be bound by the Nuclear Ban. To do so “would collide with [Germany’s] membership in NATO including nuclear deterrence.”83 Finland and Sweden were also present as observers in Vienna, though they had already moved to gain protection from Russia by joining NATO.84 Other umbrella states, like Japan and South Korea, did not send a delegation to observe the proceedings.

The case of South Korea shows just how difficult it will be for the disarmament narrative to appeal to states facing nuclear threats. In January 2023, President Yoon made off-the-cuff remarks about the need to proliferate to deter North Korea.85 Part of the discussion surrounding these comments dealt with the focus on a disarmed Ukraine being targeted by a nuclear-armed Russia.86 Yoon eventually walked back his statements about building the bomb, but South Korea received stronger U.S. assurances in April 2023 through the so-called Washington Declaration.87 Consistent with the relevant scholarship, U.S. nuclear umbrella commitments—though sometimes requiring modification—continue to be sufficient to prevent allies from proliferating. A treaty banning nuclear weapons does not seem to have much appeal at the moment for states facing challenging regional security environments.

The nuclear-armed states have also not moved in the direction of the TPNW since February 2022. Indeed, none of the nine​�ċ—Britain, China, France, India, Israel, North Korea, Pakistan, Russia, and the United States—participated in the negotiation of the Nuclear Ban. When the TPNW opened for signature, the three NATO nuclear states denigrated the treaty as “incompatible with the policy of nuclear deterrence, which has been essential to keeping the peace in Europe and North Asia for over 70 years.”88 The Trump administration also unsuccessfully attempted to pressure several states to withdraw their ratifications so that the TPNW could not enter into force in 2021.89 Such opposition is not limited to NATO’s nuclear-armed members. After the TPNW’s First Meeting of States Parties in June 2022, Russian Foreign Ministry spokeswoman Maria Zakharova condemned the treaty, stating, “devising the TPNW was premature, erroneous and, essentially, counterproductive.”90 Moscow has since used versions of this wording when discussing the TPNW in multilateral diplomatic fora.

Russia’s war on Ukraine has also made efforts to engage in nuclear arms control and eliminate nuclear stockpiles more complicated. In the past, the United States and Russia claimed to be working toward their NPT Article 6 disarmament commitments through bilateral nuclear arms control. Russia’s suspension of New START in February 2023 has therefore created serious questions about the future of arms control.91 Nearly all of the nuclear-armed states are modernizing their arsenals and expanding the role of nuclear weapons in their military doctrines. The war in Ukraine is yet another example of how the tensions of great-power competition affect the world and the nuclear order. A return to arms control, much less an embrace of the TPNW, seems unlikely given the contours of U.S.-China-Russia competition.92 Yet, these failures to deliver on the promises of Article 6 have drawn much scrutiny and critique on fairness and justice grounds at NPT Review Conferences.93

At the moment, Russia’s nuclear rhetoric seems to be accentuating existing divisions between the pro-deterrence and pro-disarmament camps. Questioning the durability of such trends is worthwhile, however. Take Germany, for example, where the Greens are in the coalition government and support joining the TPNW.94 Or consider Sweden, whose government has funded the new Alva Myrdal Centre for Nuclear Disarmament at Uppsala University and has suggested the need to create a NATO working group on nuclear disarmament after it joins the Atlantic Alliance.95 In Australia, the Labor Party committed to join the TPNW in 2018 and is now in power. Australia was an observer to the first TPNW Meeting of States Parties and in October 2022 abstained on a UN First Committee resolution on the treaty, a departure from its past opposition.96 Yet, Canberra’s “Defence Strategic Review 2023” notes, “Our best protection against the risk of nuclear escalation is the United States’ extended nuclear deterrence, and the pursuit of new avenues of arms control.”97 Still, it is not unreasonable to believe that, as time passes, the appeal of the Nuclear Ban will return in democratic states with U.S. nuclear umbrella pledges. While Putin’s nuclear threats may initially cause shock and bolster the nuclear deterrence narrative, they also provide evidence that could ultimately enhance the nuclear disarmament narrative and require alterations to the structure of military alliances.
 

Endnotes

• 59Hans M. Kristensen, Matt Korda, and Eliana Reynold, “,” Bulletin of the Atomic Scientists 79 (3) (2023): 175.
• 60“,” BBC News, June 17, 2023.
• 61Adérito Vicente, Polina Sinovets, and Julien Theron, eds., (Cham, Switzerland: Springer, 2023).
• 62Kristensen, Korda, Reynolds, and Kohn, “Status of World Nuclear Forces.”
• 63Hans M. Kristensen and Matt Korda, “,” Bulletin of the Atomic Scientists 79 (1) (2023): 43.
• 64François Diaz-Maurin, “,” Bulletin of the Atomic Scientists, October 20, 2022.
• 65See, for example, Budjeryn, Inheriting the Bomb.
• 66Murtaza Hussain, “,” The Intercept, February 27, 2022.
• 67Stephen Herzog, “,” Georgetown Journal of International Affairs 18 (3) (2017): 67–78.
• 68Jeffrey W. Knopf, “,” in Security Assurances and Nuclear Nonproliferation, ed. Jeffrey W. Knopf (Stanford, Calif.: Stanford University Press, 2012), 24.
• 69Francesca Giovannini, “,” Arms Control Today 52 (6) (2022): 7.
• 70Benoît Pelopidas, “,” The Nonproliferation Review 18 (1) (2011): 297–314.
• 71J. Luis Rodríguez and Elizabeth Mendenhall, “,” International Affairs 98 (3) (2022): 819–836.
• 72Müller and Wunderlich, “Nuclear Disarmament without the Nuclear-Weapon States.”
• 73Gibbons and Herzog, “The First TPNW Meeting and the Future of the Nuclear Ban Treaty,” 13.
• 74“Draft Vienna Declaration,” 2.
• 75Gibbons and Herzog, “The First TPNW Meeting and the Future of the Nuclear Ban Treaty,” 15–16; and Andrew Futter and Olamide Samuel, “,” Review of International Studies, August 18, 2023.
• 76Matias Spektor, “,” Foreign Affairs 102 (3) (2023): 8–16.
• 77J. Luis Rodríguez and Christy Thornton, “,” Cambridge Review of International Affairs 35 (5) (2022): 626–638; and Spektor, “In Defense of the Fence Sitters.”
• 78United Nations, Office for Disarmament Affairs, “Treaty on the Prohibition of Nuclear Weapons: Status of the Treaty.”
• 79See, for example, Mathy, “Why Do States Commit to the Treaty on the Prohibition of Nuclear Weapons?”
• 80For a discussion of reasons why states might join universal arms control and disarmament treaties, see Jan Karlas, “,” Contemporary Security Policy 44 (3) (2023): 410–436.
• 81Observers included the following states without nuclear security guarantees: Brazil, the Democratic Republic of the Congo, Indonesia, Libya, the Marshall Islands, Morocco, Nepal, and Switzerland. Also taking part were a handful of states under the U.S. nuclear umbrella: Australia, Belgium, Germany, the Netherlands, Norway, and NATO applicants Finland and Sweden.
• 82“,” Vienna, June 21, 2022.
• 83“” (presented at the First Meeting of States Parties to the Treaty on the Prohibition of Nuclear Weapons, Vienna, June 21–23, 2022).
• 84Alberque and Schreer, “Finland, Sweden and NATO Membership.”
• 85Choe Sang-Hun, “,” The New York Times, January 12, 2023.
• 86Pak, “Korea Looks to Europe.”
• 87The White House, “,” April 26, 2023.
• 88Casey-Maslen, The Treaty on the Prohibition of Nuclear Weapons, 52.
• 89Névine Schepers, “,” CSS Analyses in Security Policy (286) (June 2021): 2.
• 90Quoted in “,” Interfax News Agency, June 24, 2022.
• 91Bugos, “Russia Suspends New START.”
• 92David M. Allison and Stephen Herzog, “,” Bulletin of the Atomic Scientists 76 (4) (2020): 200–205; and Alexey Arbatov, David Santoro, and Tong Zhao, “,” in IFSH Research Report 2, ed. Ulrich Kühn, Institute for Peace Research and Security Policy in Hamburg (March 2020).
• 93See, for example, Steven E. Miller, Nuclear Collisions: Discord, Reform and the Nuclear Nonproliferation Regime, with responses from Wael Al-Assad, Jayantha Dhanapala, C. Raja Mohan, and Ta Minh Tuan (Cambridge, Mass.: American �����Ƶ of Arts and Sciences, 2012); and J. Luis Rodríguez, “” Monkey Cage [blog], The Washington Post, August 1, 2022.
• 94International Campaign to Abolish Nuclear Weapons, “” (accessed October 3, 2023).
• 95Ann-Sofie Nilsson, , October 19, 2022.
• 96International Campaign to Abolish Nuclear Weapons, “” (accessed October 3, 2023).
• 97Australian Government, (Canberra: Commonwealth of Australia, 2023), 37.

The Public and Nuclear Disarmament

Government policy on nuclear weapons represents only one side of the discussion on the future prospects for the TPNW. Less immediate, but perhaps equally important, is the role of public opinion, particularly in democratic states that possess nuclear weapons or rely on extended nuclear deterrence. Beatrice Fihn, former executive director of the Nobel Peace Prize–winning International Campaign to Abolish Nuclear Weapons (ICAN), has explained that the public is crucial to the Nuclear Ban campaign. In an interview, Fihn stated that “politicians are very sensitive to changes in public opinion” and that this would be a mechanism for change.98 Essentially, the Nuclear Ban movement is premised on an idea of long-term, bottom-up political change.

Whether that mechanism can be successful in inspiring nuclear disarmament remains to be seen. What can be done now is to evaluate recent trends in public opinion. We do so here within the context of the United States and its international alliances. As these states are the democracies under greatest pressure and scrutiny from the Nuclear Ban campaigners, the views of their publics provide benchmarks for understanding the challenges that lie ahead for the TPNW. We find that the debate over the TPNW is largely unsettled, although many of these publics are moving away from nuclear disarmament as nuclear salience increases.

Before the war in Ukraine, the academic literature on opinion toward the TPNW showed mixed results.99 Stephen Herzog, Jonathan Baron, and Rebecca Davis Gibbons noted that, while 65 percent of Americans supported the Nuclear Ban in principle, only 26 percent claimed to have heard of it. When the U.S. public was presented with realistic government rhetoric critiquing the treaty, support fell to below a majority.100 A parallel study in Japan, however, concluded that the Japanese government could not effectively counter the 75 percent support rate for the TPNW among its public.101 And in the Netherlands, Michal Onderco and colleagues found that the Dutch public was only really interested in joining the Nuclear Ban alongside other members of NATO.102

Another frequently mentioned example of prewar public support for the TPNW is the ICAN Cities Appeal. This initiative encourages local and regional legislative bodies to endorse the TPNW in resolutions even if their national governments do not support the treaty. Several hundred of these bodies had joined prior to the war in Ukraine, and more continue to do so.103 This is a considerable accomplishment and analogous to efforts by the campaign to have localities endorse the Paris Climate Accords. Few of these resolutions receive popular endorsement through a referendum or other ballot measure, however, so they do not help to establish a useful baseline measurement of public views. Further polling would be required to assess the relationship between local nuclear disarmament resolutions and public opinion.

Polling since February 2022 also indicates shifts in European public opinion toward nuclear weapons that should disturb Nuclear Ban campaigners. Putin’s war in Ukraine and his nuclear threats appear to have made populations more supportive of having nuclear protection pledges. This response likely reflects the fear that European publics continue to experience given their proximity to both Ukraine and Russia. News in Europe regularly includes stories about nuclear weapons effects, the locations of bunkers and other shelters, and instructions on how to survive a nuclear attack. Unfortunately, this is to be expected with Putin’s rhetoric and Russia’s behavior. Since this war began, the world has seen reckless Russian strikes at the Zaporizhzhia Nuclear Power Plant, the Kremlin’s use of conventionally armed but nuclear-capable missiles against Ukrainian civilians, and Russian state media simulating nuclear strikes on Berlin, London, and Paris.104 Citizens in some European states have even stockpiled iodine pills to provide protection in the case of exposure to radiation.105 Increased nuclear salience in Europe could eventually lead to more support for the TPNW. As of now, it has usually been accompanied by government messaging about the centrality of NATO and the security the alliance provides to its members.

One key piece of evidence pertains to public opinion on the NATO membership applications of Finland and Sweden, submitted just months after the war began. Tuomas Forsberg reports that a small, stable minority of just 20–30 percent of Finns supported NATO accession for decades following the Cold War. Then, “public opinion changed dramatically almost overnight during the week the war broke out in late February.” By May 2022, 76 percent of the population favored joining NATO.106 The situation was slightly different in Sweden, where a plurality had supported joining NATO prior to the war. By April 2022, this number had risen to 53 percent.107 To be sure, NATO membership has benefits beyond protection with nuclear arms. Nonetheless, these polling results show the Finnish and Swedish publics embracing an explicitly nuclear-armed alliance.

Another survey-based academic study directly addresses how the war in Ukraine may have affected attitudes regarding nuclear weapons. Onderco and colleagues employed a two-wave recontact study. They found Dutch and German citizens to be more hawkish on nuclear issues in June 2022 than in September 2020. The results from both countries suggest an increase in the perceived deterrent value of nuclear arms and in willingness to support the use of these weapons.108 Along the same lines, the news program Tagesschau conducted a poll in summer 2022 that found, for the first time, a majority of Germans—52 percent—now wanting to retain long unpopular U.S. tactical nuclear weapons on their country’s soil.109 These sorts of polling numbers sharply contrast with findings from a 2019 survey. That study suggested that a majority of Europeans in nine countries—including over 70 percent of Germans—wanted their governments to push for nuclear abolition.110 Such results over time indicate that the deterrence narrative may be catching on with certain European publics at the expense of the disarmament narrative and the TPNW.

In Central and Eastern Europe, endorsement of the Nuclear Ban also seems unlikely to gain popularity with the public at present. Lauren Sukin and Alexander Lanoszka polled Estonians, Latvians, Lithuanians, Poles, and Romanians early on in the war in Ukraine. Their study found very high confidence in the United States, NATO, and nuclear policymaking within the Atlantic Alliance. At the same time, public support for national nuclear proliferation was surprisingly high for countries under the U.S. nuclear umbrella, even constituting a majority in Poland, whose government is now also interested in hosting American tactical nuclear weapons.111 Strong public support in umbrella states for nuclearization is not an entirely new phenomenon. For example, polling has shown stable majority public support for proliferation in South Korea for over a decade.112 Whether these views will actually result in proliferation remains to be seen. Politicians in Poland and South Korea have thus far seemed content with different variations of U.S. security assurances. What is clear, however, is that public opinion of the sort registering across North America, Europe, and East Asia does not translate into support for the TPNW.

Among Americans, December 2022 polling of a nationally representative sample indicated that 69 percent of people had increased nuclear anxieties. Respondents were “extremely or somewhat concerned about the possibility of a nuclear war in the next five years,” marking an 8 percent increase from the previous year.113 Although the results show greater concern about a potential nuclear war, this increase is considerably less than might be expected given many months of media coverage of nuclear threats from Putin. The poll also does not provide any information about whether these fears will translate into greater support for nuclear deterrence or for nuclear abolition. Both are conceivable.

In January 2023, David Allison and colleagues assessed support for the TPNW among the U.S. population. The authors told some U.S. respondents that Russia, China, and other nuclear-armed states had not joined the TPNW and then asked them if they thought the United States should ratify the treaty. A plurality of respondents did not favor ratification. In total, the study found that 37 percent of Americans supported ratification under the current international circumstances, compared to 44 percent who did not and 19 percent who were undecided.114 The results suggest that any future entry of the United States into the TPNW would need to be done alongside Washington’s rivals.

Surveys provide snapshots of public views at specific moments in time, so results can vary as world events unfold. That said, how might we interpret this January 2023 polling evidence? Public opinion about nuclear weapons since the onset of Russia’s full-scale invasion of Ukraine represents early reactions to the crisis. People, particularly in Europe, are now dealing with emotions of fear and surprise as they grapple with the unpleasant nuclear realities laid out by Alexander Bollfrass and Stephen Herzog:

In making nuclear threats overt, Putin has focused public attention on nuclear dynamics and processes usually consigned to obscure technocratic and elite activity. In Europe, each Russian threat has illuminated once-suppressed nuclear facts of life. Helpless publics are waking up to the harsh truth that there is no reliable protection against city-destroying nuclear-armed missiles that can arrive from Russia in under half an hour. Meanwhile, the tool on display to prevent such horrific devastation is a promise that France, the UK and the US are threatening to retaliate in kind if a Russian missile lands on NATO territory. This is, after all, the world of nuclear deterrence based on “mutual assured destruction” created and refined in the aftermath of the Second World War.115

For now, the result of increased nuclear salience in many countries has been greater endorsement of a nuclear deterrence posture and a desire for strengthened U.S. nuclear security guarantees. Nuclear Ban advocates are also using this moment to communicate with the public about nuclear risks in the hope of starting a more open debate with deterrence advocates, most of whom have been content to ignore the TPNW.

This moment of growing support for nuclear deterrence need not last forever. Putin’s nuclear threats have dramatically increased the salience of nuclear weapons. In late February 2022, worldwide Google searches for some nuclear weapons–related topics were hundreds of times higher than in previous days. A “new normal” for nuclear salience was quickly established as the media and experts rushed to explain the bomb to anxious publics. For the moment, public views appear to largely mirror those of government policy. But the debate over the TPNW and nuclear disarmament is still new to the public, marked by indecision and knowledge gaps, and thus unsettled. Over time, the dangers of nuclear weapons that have manifested during the war in Ukraine could help shift public views toward disarmament.

Conversely, the global public could also move past fears of nuclear weapons after the war in Ukraine ends, or even during it if the conflict stalemates. A return to the public apathy toward nuclear weapons that characterized much of the post–Cold War period is not outside the realm of the possible. Were this to occur, further movement toward disarmament would seem unlikely absent strong activism to keep nuclear dangers in the public eye.
 

Endnotes

• 98Quoted in Mekata, “How Transnational Civil Society Realized the Ban Treaty,” 89.
• 99This contrasts with polling commissioned by ICAN, which has generally found overwhelming support for the TPNW. See International Campaign to Abolish Nuclear Weapons, “,” January 2021.
• 100Stephen Herzog, Jonathon Baron, and Rebecca Davis Gibbons, “,” The Journal of Politics 84 (1) (2022): 591–596.
• 101Jonathon Baron, Rebecca Davis Gibbons, and Stephen Herzog, “,” Journal for Peace and Nuclear Disarmament 3 (2) (2020): 299–309.
• 102Michal Onderco, Michal Smetana, Sico van der Meer, and Tom W. Etienne, “,” The Nonproliferation Review 28 (1–3) (2021): 149–163.
• 103International Campaign to Abolish Nuclear Weapons, “” (accessed October 3, 2023).
• 104Yuliya Talmazan, “,” NBC News, May 14, 2022.
• 105Maddie Burakoff, “,” Los Angeles Times, October 13, 2022.
• 106Tuomas Forsberg, “,” PRIO Blogs, Peace Research Institute Oslo, May 9, 2022.
• 107Ibid.
• 108Michal Onderco, Michal Smetana, and Tom W. Etienne, “,” Global Policy 14 (2) (2023): 305–317.
• 109Robert Bongen, Hans-Jakob Rausch, and Jonas Schreijäg, “” [Poll: Majority in Favor of Nuclear Weapons in Germany for the First Time], Tagesschau, June 2, 2022.
• 110Kjølv Egeland and Benoît Pelopidas, “,” European Security 30 (2) (2021): 247.
• 111Lauren Sukin and Alexander Lanoszka, “,” Bulletin of the Atomic Scientists, April 15, 2022.
• 112See, for example, Toby Dalton, Karl Friedhoff, and Lami Kim, “,” Chicago Council on Global Affairs, February 2022.
• 113Greg Hadley, “,” Air and Space Forces Magazine, December 2, 2022.
• 114David M. Allison, Giles David Arceneaux, Rebecca Davis Gibbons, and Stephen Herzog, “Does Nuclear Disarmament Activism Work? Global Advocacy in Local Politics” (unpublished working paper, 2023).
• 115Bollfrass and Herzog, “The War in Ukraine and Global Nuclear Order,” 20.

The Nuclear Use Question

Trends in state behavior and public opinion could completely change if Moscow resorted to the nuclear option to decisively alter the course of its war with Ukraine. Fears of this nature have gained traction as Russian military setbacks in Ukraine have accumulated.116 No one except Putin knows the actual likelihood that Russia will cross the nuclear threshold in the context of the war. Nuclear weapons use remains unlikely, even as its probability has increased since February 2022. Attaching a percentage to the potential for nuclear use is exceedingly difficult, though some experts have tried.117 More apparent than the likelihood of nuclear use is the conclusion that a nuclear detonation would inevitably carry monumental political consequences for the global nuclear order. Were Putin to order the use of a nuclear weapon, however, the result could either strengthen arguments in favor of the Nuclear Ban or bolster the position of those relying on nuclear deterrence. The main determinant of this outcome would depend on the effects of a strike and on whether nuclear use was seen to be militarily and politically beneficial to Russia.

Russian nuclear threats during the war in Ukraine have sparked both outrage and media fixation, but they are hardly the first such threats during the atomic age. For example, analysts from the Stimson Center tracked more than seventy overt nuclear threats made by leaders from 1970 to 2010.118 Since then, many additional threats have been made, including Donald Trump’s memorable “fire and fury” Twitter spat with North Korean Supreme Leader Kim Jong Un. Unpalatable as nuclear threats may be to members of the public, they are central to the strategy of nuclear deterrence and to making nuclear strikes credible in the minds of adversaries. Despite many of these threats, nuclear use has not occurred since 1945. But due to their relationship with nuclear escalation and coercion, nuclear threats are strictly prohibited by the TPNW and were condemned in the Vienna Declaration of the treaty’s First Meeting of States Parties. Putin’s nuclear threats are already contributing to polarization between disarmament and deterrence proponents.

If these threatening actions short of nuclear use can affect state positions, what might happen if Russia really did use nuclear weapons? Academic research offers several possibilities for how governments and states might respond to nuclear strikes. The literature is clear that such reactions are context dependent. In some cases, nuclear use could prompt greater interest in seeking nuclear weapons for national security. In other cases, a nuclear attack might reaffirm antinuclear norms by showing the world the horrors of the immediate and longer-term effects of nuclear explosions. These theoretical predictions provide insights into what events might unfold if the Kremlin were to resort to the nuclear option. Like Putin’s nuclear threats, the possibilities discussed in the literature point to results in both directions. However, the first use of nuclear weapons since 1945 is likely to be a global tragedy, one with much more normative unifying power than nuclear deterrent threats. Such was the extent of mass human suffering inflicted in Hiroshima and Nagasaki that it created a nuclear taboo that has stood for over seventy-five years.

George Quester examines several factors that could affect the durability of the nonuse norm after a violation of the taboo. These considerations include the extent of damage caused by the detonation, the strategic consequences of nuclear use, the identity of the attacker and target, and the international response.119 On this last point, Tannenwald writes that, after nuclear use, “the international community would have to respond with extremely strong measures to reconstruct and strengthen [the taboo].”120 Keir Lieber and Rebecca Davis Gibbons also make predictions about the durability of the norm after nuclear first use in warfare. In line with Quester’s point about damage, they propose that a “dramatic demonstration of the abhorrent consequences of nuclear weapons use could serve to reinforce subsequent adherence” to antinuclear norms. This could potentially induce states to join the TPNW. But use with limited civilian effects could send the opposite message.121 The latter scenario could result in new ideas about the “usability” of nuclear weapons in conflict, which strikes at the core of the objectives of the Nuclear Ban Treaty.

A second key factor in determining how nuclear use is perceived is its strategic effectiveness. Put simply, does using the bomb accomplish an actor’s objectives? If the Kremlin is able to use nuclear weapons and force the government in Kyiv to surrender, observers will see that nuclear arms are pivotal to achieving victory in war. States and publics that currently view nuclear weapons as beneficial tools for providing security will remain unsympathetic to the arguments of TPNW supporters. In fact, more states may be incentivized to pursue the bomb to enhance their power or to avoid the tragic fate of Ukraine. Also plausible is that some TPNW proponents will no longer want to be constrained by the obligations of the Nuclear Ban given the world’s grave nuclear dangers, though much would depend on the damage and humanitarian impacts of any attack.

The literature suggests that a perceived “effective use” with relatively low collateral damage would signal that nuclear weapons are useful and less horrific than previously believed. Some states and their publics might thus decide that nuclear possession is desirable and nuclear use permissible. Were this to occur, antinuclear norms and the TPNW would both face monumental setbacks. In contrast, nuclear use that does not allow Russia to achieve victory, that kills thousands of civilians, and that spreads radiation to surrounding areas will contribute to the rejection of nuclear weapons.

A nuclear explosion in a densely populated area would remind the world of the devastating humanitarian impacts of these weapons.122 Thousands of people around the epicenter of the attack would die immediately from buildings collapsing from the blast wave, many more would succumb to spreading fires, and others would perish from radiation sickness.123 The imagery would likely galvanize a meaningful portion of the public and states around the world to call for nuclear disarmament. The TPNW would offer a policy option to these parties, as it already does to many who are appalled by Putin’s nuclear threats and the risks associated with the Ukraine war. A strategically “successful” nuclear attack that causes mass civilian casualties may pull states in the direction of either disarmament or deterrence, but its physical effects and imagery would be sickening and impossible to deny.

A use of nuclear weapons that is not “cinematic,” however, could degrade norms against using the bomb.124 One potential scenario is a Russian “demonstration shot” over an unpopulated area to convince the Ukrainians into surrendering or ceding territory to Moscow. While this type of nuclear weapon use could theoretically bring the conflict to an end without killing thousands, it would not demonstrate the full destructive effects of nuclear weapons. The lack of significant casualties would risk blurring the normative bright line between conventional weapons and their nuclear counterparts. Alternatively, if a demonstration shot did not work to compel Ukrainian leaders to surrender, it might be read as unwillingness to use nuclear weapons in a populated area. This could undermine Russia’s nuclear prowess, potentially pressuring Putin to use nuclear arms against a populated area. If nuclear arms come to be seen by leaders and the public as a less taboo form of weaponry, the likelihood of their use in future conflicts will grow. This could put humanity on the path toward escalation to a strategic nuclear exchange that threatens all life on the planet.125

The security value of nuclear weapons has already been demonstrated in Ukraine, however. NATO has avoided direct involvement in the war even as Russia has repeatedly and indiscriminately targeted civilians and committed grievous violations of human rights. Putin’s nuclear threats lie at the heart of the West’s inability to have boots on the ground or to implement a no-fly zone in the air over Ukraine. The lesson appears to be that nuclear weapons can shield military aggressors from outside intervention. If Russia, in spite of its poor battlefield performance, is able to defeat Ukraine, that would also send a clear message about the utility of nuclear weapons.126 The successful prospects of the TPNW and related antinuclear norms are thus inextricably linked to the outcome of this war and the salience of the challenge posed by nuclear arms.
 

Endnotes

• 116Masha Gessen, “,” The New Yorker, November 1, 2022.
• 117For example, in an interview with National Public Radio (NPR) in October 2022, Harvard Kennedy School professor Matthew Bunn estimated the likelihood of Putin using a nuclear weapon in the war in Ukraine at 10–20 percent. See NPR, “” Up First, NPR, October 4, 2022.
• 118Samuel Black and Shireen Havewala, “,” Stimson Center, March 31, 2010.
• 119George Quester, (Baltimore: Johns Hopkins University Press, 2006).
• 120Nina Tannenwald, “,” International Security 29 (4) (2005): 38.
• 121Rebecca Davis Gibbons and Keir Lieber, “” Journal of Strategic Studies 42 (1): 29–52.
• 122For a sense of the devastation that would be caused by nuclear weapon use, see Alex Wellerstein, (accessed October 3, 2023).
• 123On the effects of nuclear weapons, see, for example, Samuel Glasstone and Philip J. Dolan, , 3rd ed. (Washington, D.C.: U.S. Department of Defense, 1977); and Lynn Eden, Whole World on Fire: Organizations, Knowledge, and Nuclear Weapons Devastation (Ithaca, N.Y.: Cornell University Press, 2004).
• 124Tom Whipple, “,” The Times (London), October 15, 2022.
• 125On the planetary dangers of nuclear war, see, for example, Zia Mian and Benoît Pelopidas, “,” in How Worlds Collapse: What History, Systems, and Complexity Can Teach Us about Our Modern World and Fragile Future, ed. Miguel Centeno, Peter Callahan, Paul Larcey, and Thayer Patterson (New York: Routledge, 2023), 315–332.
• 126On Russian battlefield performance in Ukraine, see, for example, Robert Dalsjö, Michael Jonsson, and Johan Norberg, “,” Survival 64 (3) (2022): 7–28.

The TPNW in a World of Increased Nuclear Salience

On November 20, 1983, approximately one hundred million Americans—a significant portion of the national population—viewed the film The Day After on television. The film’s showing came at a time of particularly high tensions during the Cold War. After watching intercontinental ballistic missiles detonate over communities in Kansas and Missouri, Americans watched in horror as survivors suffered in the aftermath of the fictional attack. One notable account of the event summarized the effects of nuclear weapons as follows:

We see virtually an entire populace reduced to vaporized silhouettes. We see blistered and blinded human gargoyles suffer slow death from radiation sickness. We see the crumbling of a society’s restraints: the most law-abiding citizens emerge from the rubble of ground zero to loot, rape and pillage. As firing squads add to the mass graves, a few valiant survivors struggle to reconnect the severed communal bonds that distinguish life from mere existence. But their efforts erode as relentlessly as the deathly white ash that wafts down upon the blackened fields.127

The Day After still holds the national record for U.S. television movie viewership. It undoubtedly increased the salience of nuclear weapons among the American public and reminded people of the potential devastation wrought by nuclear use.128 Yet, surveys of Americans following the film’s showing revealed surprising results. Researchers found that individuals knew more about the effects of nuclear weapons, but the film did not change people’s overall views about nuclear weapons and deterrence. Instead, it solidified their existing perspectives.129 Those in favor of disarmament saw the film as strong evidence for nuclear abolition. Those in favor of deterrence redoubled their commitment to nuclear deterrence to protect the United States from such attacks.

A comparison of the nuclear dynamics of the war in Ukraine and The Day After seems apt. Four decades after the film aired, world events and great-power competition have spelled the return to public view of nuclear weapons, disarmament, and deterrence. The result of Putin’s nuclear threats and employment of nuclear deterrence to shield his war against NATO intervention has likewise polarized international observers. The evidence shows that such trends are present at the level of both national governments and public opinion. Proponents of nuclear disarmament who favor the TPNW have found much support for their position in thinking about the risks that accompany threats of nuclear use. But for those actors who already believed in the value of nuclear weapons for national security, the lesson of the war is a confirmation of the need for nuclear deterrence postures. Thus, we are now witnessing the intensified polarization of existing opinions surrounding the legitimacy of nuclear weapons as tools of statecraft.

Unfortunately, researchers did not examine the long-term impact of viewing The Day After. Perhaps viewers remained staunchly committed to their previous positions even decades later. Perhaps over time their ideas about nuclear weapons changed. Or perhaps memories of the film dissipated and had no durable effects on nuclear attitudes. This topic is particularly relevant because it is unclear how increased nuclear salience surrounding the war in Ukraine will evolve on the international stage and in the public mindset. Of course, viewing a fictional account of nuclear use on television is considerably different from being bombarded with real-world media coverage about an adversarial leader threatening to use nuclear weapons.130

Just as the views of Finns toward NATO changed “overnight” after Russia’s invasion of Ukraine, global opinion could change quickly with actual nuclear use. A nuclear attack that shocks the conscience and yields human and structural devastation may lead the public and leaders to shift their attitudes definitively against nuclear weapons and toward the TPNW. If nuclear use were to appear more benign due to a detonation in an unpopulated land area like a forest, or over a body of water, norms against nuclear weapons and their use might weaken. Given this environment of uncertainty, what might states do in the global nuclear order in the coming years?

States and activists promoting the TPNW will likely face difficulties in attempting to universalize the treaty to states that depend on nuclear weapons. For this reason, many of the discussions at the Vienna Meeting of States Parties focused on Article 12 of the TPNW, which pertains to universalization.131 TPNW proponents will continue to work to develop the treaty institutionally. A Nuclear Ban that is more universal and more verifiable will have greater appeal among governments and their publics. In the meantime, Nuclear Ban campaigners are likely to continue to use Russian nuclear threats and transgressions in their outreach efforts to educate the global public about the TPNW. Since nuclear-armed states and their allies are unlikely to budge on disarmament at the moment, one strategy that might work to gain concessions is issue linkage. A recent example of this is the Marshall Islands’ successful demand for additional nuclear testing impacts compensation from the United States in exchange for continued military basing rights.132

For its part, Washington still has much to do in response to the nuclear dimensions of the war in Ukraine. The rhetoric of South Korean President Yoon and public opinion polls in several allied states indicate that nuclear fears may translate into a desire for the bomb. Preventing nuclear proliferation from occurring under the umbrella will require a revitalized U.S. commitment to nonproliferation and even some flexibility in renegotiating security partnerships with allies. These pressures are likely to remain as the United States and NATO simultaneously seek to avoid a nuclear confrontation or unintended escalation with Russia.

Finally, the events that have occurred since February 2022 have firmly positioned disarmament as the dominant alternative to the nuclear status quo. The TPNW is the most prominent instrument that is part of this narrative. The policies of the nuclear status quo have led to nuclear coercion in the center of Europe, continual arsenal modernizations, and a retreat from the policies of arms control that once gave some level of credibility to the great powers’ disarmament commitments under Article 6 of the NPT. The global nuclear order is not collapsing, but its inequities have become all too visible as a result of Russia’s war in Ukraine. Nuclear issues may yet hamper U.S. relations with the Global South. And if the TPNW has a resurgence in appeal in Europe or Australia, this could lead to fundamental changes in the structure of U.S. defense alliances. Continuing to ignore the Nuclear Ban Treaty would be naive, as it is in the interests of the United States and its allies to recognize the motivations underlying this movement and treaty. Though near-term acceptance of the TPNW by nuclear-armed and umbrella states does not appear to be in the cards, these countries should consider ways to address the concerns raised by Nuclear Ban proponents in the Global South and beyond. Serious intra-alliance consultations and joint policymaking toward the TPNW would be wise, as would more unified observer participation at future treaty meetings.
 

Endnotes

• 127Quoted in Stanley Feldman and Lee Sigelman, “” The Journal of Politics 47 (2) (1985): 556–557.
• 128Deron Overpeck, “,” Historical Journal of Film, Radio and Television 32 (2) (2012): 267–292.
• 129Feldman and Sigelman, “The Political Impact of Prime-Time Television,” 557–558.
• 130Some scholarship does, however, indicate that “synthetic experiences” can influence both the public and policymakers. See, for instance, J. Furman Daniel III and Paul Musgrave, “,” International Studies Quarterly 61 (3) (2017): 503–516.
• 131Gibbons and Herzog, “The First TPNW Meeting and the Future of the Nuclear Ban Treaty.”
• 132Daryl G. Kimball, “,” Arms Control Today 53 (2) (2023): 30–31.

Acknowledgments

The authors are grateful for feedback along the way from David M. Allison, Alexander K. Bollfrass, Doreen Horschig, Steven E. Miller, J. Luis Rodríguez Aquino, Wilfred Wan, and Heather Williams. The authors also benefited from conversations with the Nuclear Negotiations Working Group of the Alva Myrdal Centre for Nuclear Disarmament at Uppsala University and editorial suggestions from Phyllis Bendell and Christopher Davey.