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On February 24, 2022, Russia invaded nonnuclear-armed Ukraine and leveraged threats with its nuclear arsenal as a “shield” to deter third-party intervention. The well-publicized horrors on the ground in Ukraine are, unfortunately, not the only consequences of Russia’s full-scale invasion of its neighbor. The war is having unmistakable effects on how governments, scholars, and the public think about nuclear arms. Not only has Moscow reintroduced the world to the often-unsavory realities of nuclear deterrence, but its suspension of the New Strategic Arms Reduction Treaty (START) and deratification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) have been setbacks for arms control and disarmament. Meanwhile, vulnerable states around the globe may be further incentivized to develop nuclear weapons or seek protection from nuclear-armed patrons to avoid being invaded like Ukraine.

Given these changing geopolitical circumstances, how might the Russian war on Ukraine affect the global nuclear order? The authors in this publication conclude that the United States and the broader international community must now more seriously engage with alternatives to traditional arms control, nonproliferation, and disarmament endeavors. Specifically, the authors discuss the increasing prominence of approaches such as the Treaty on the Prohibition of Nuclear Weapons (TPNW)—popularly known as the Nuclear Ban—and risk reduction measures. They assess whether these initiatives can have an impact in reducing nuclear dangers. Additionally, they examine temptations for states to pursue more forceful counterproliferation measures and describe the risks of doing so.

This publication proceeds in three sections as it unpacks challenges to the global nuclear order presented by Russia’s war. First, Rebecca Davis Gibbons (University of Southern Maine) and Stephen Herzog (Center for Security Studies at ETH Zurich) explore how prospects for the success and failure of the TPNW have been altered by the shifting nuclear landscape. Next, Wilfred Wan (Stockholm International Peace Research Institute) analyzes risk reduction measures in light of growing nuclear modernization and arms control backsliding, highlighting how this approach can involve multiple players and address technological hurdles. Finally, Doreen Horschig (Center for Strategic and International Studies) discusses a possible turn to counterproliferation, as instruments of the nonproliferation regime may falter, and outlines the risk of resorting to the use of force against nuclear weapons programs.
 

“Nuclear Disarmament and Russia’s War on Ukraine: The Ascendance and Uncertain Future of the Treaty on the Prohibition of Nuclear Weapons” by Rebecca Davis Gibbons and Stephen Herzog

In their essay, Rebecca Davis Gibbons and Stephen Herzog assess how the nuclear dynamics of Russia’s war on Ukraine have impacted the TPNW’s efforts to eliminate nuclear weapons. The authors evaluate predictions from scholarly literature, evolving state positions, implications for public opinion, and how actual nuclear weapon use may alter the international climate. They conclude that the war has exacerbated a schism between those who advocate for nuclear disarmament and those who favor nuclear deterrence. They also conclude that great-power competition between the United States, China, and Russia undermines the notion of traditional phased U.S.-Russia arms control as a driver of nuclear disarmament.

Many observers have argued that the war in Ukraine incentivizes nuclear proliferation among nonnuclear states. Yet, of the more than thirty states that initiated nuclear weapons programs, just ten acquired the bomb. Gibbons and Herzog highlight several reasons from the social scientific literature explaining why this is the case: the role of alliances with nuclear-armed states, U.S. efforts to prevent nuclear proliferation, managerial challenges of building nuclear weapons, and strong norms against nuclear weapons development and use.

Among states, the authors note that two nuclear narratives are prominent from Russia’s war on Ukraine: nuclear disarmament and nuclear deterrence. The first addresses the dangers presented by wars involving nuclear-armed states and champions disarmament and the TPNW. The second recognizes these dangers but concludes that the way to achieve security is increased reliance on nuclear deterrence and extended deterrence, not the TPNW. The result is much greater polarization in international nuclear politics, particularly in multilateral fora.

Gibbons and Herzog argue that these divisions may also affect publics, the key audience for many Nuclear Ban outreach efforts. Most publics around the world have not confronted such vivid nuclear risks since the Cold War. While attitudes in nuclear-armed states and their allies appear to be turning toward deterrence and away from disarmament, the authors argue it is still too early to conclude how this war will shape views toward the bomb worldwide.

One scenario that will likely have considerable effects would be the use of nuclear weapons by Russia in its war on Ukraine. The literature suggests that if nuclear weapon use is strategically effective and carries limited collateral damage, this could lead some governments and publics to more readily accept the nuclear deterrence narrative. But if nuclear use does not contribute to a Russian victory and/or results in mass casualties, the appeal of nuclear weapons should plummet. This would buttress the disarmament narrative. Overall, how the war ends, and what role nuclear weapons do, or do not, play in the outcome, will have long-standing implications for the global nuclear order.

Regardless, the authors conclude that disarmament is now the dominant alternative to the nuclear status quo, and the TPNW is the principal tool in promoting it. As the authors point out, the global nuclear order has so far withstood Russian transgressions, but its inequities have become increasingly visible. These are the injustices that, in part, motivated the creation of the TPNW, which is proving its staying power. Continuing to ignore the treaty could risk the great powers’ credibility on nonproliferation and disarmament, their relationships with the Global South, and the continuity of their military alliances. It is therefore in the interests of the United States and its allies to acknowledge the concerns of Nuclear Ban proponents and begin finding ways to address them.
 

“Wither Nuclear Risk Reduction?” by Wilfred Wan

In his essay, Wilfred Wan assesses the state of nuclear risk reduction. In doing so, he outlines risk reduction concepts and operational challenges, reflects on past efforts during and after the Cold War, examines risk reduction in light of the Russia-Ukraine War, and highlights recommendations for revitalizing it going forward. He emphasizes that reducing the probability of nuclear use will require political, strategic, operational, and technical steps at national, bilateral, and multilateral levels.

Nuclear modernization programs, including those involving states outside the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), have enhanced the role of nuclear weapons. In this context, Wan argues that risk reduction is crucial in preventing miscalculation and accidental detonation during crises among adversarial states, and it can also improve the safety and security of existing stockpiles and materials. He outlines risk reduction efforts by the Soviet Union and the United States during the Cold War, which centered on 1) mutual recognition of an unacceptable level of risk; 2) transparency, information exchange, and behavioral restraint; 3) restrictions in capabilities; and 4) strategic dialogue.

Wan notes that when Russia invaded Ukraine on February 24, 2022, the risk calculus of some states changed, impacting their views on the utility of nuclear weapons. While the war’s long-term impact on the global nuclear order is to be determined, the specter of nuclear escalation between Russia and the West linked to that war remains.

Wan also points out the subjectivity of risk assessments and the variability of risk thresholds, which can present obstacles to multilateral risk reduction efforts. He notes the difficulty of creating consensus-based policies through bilateral and multilateral risk reduction efforts, but argues that Russian involvement will eventually be necessary, as Russia has the largest nuclear weapons stockpile. Although Russa and the United States have engaged in some limited confidence-building measures even during the war in Ukraine, Wan highlights a resultant backsliding in transparency, information exchange, and behavioral restraint. This is especially concerning since the only agreement in place with limits on the size and composition of Russian and U.S. nuclear arsenals, New  START, is suspended and set to expire in 2026.

To revitalize nuclear risk reduction efforts, Wan recommends the following:

• Expand the approach to be multifaceted and multidomain, including by enhancing broader military transparency.
• Address technological concerns, including advances in nonnuclear capabilities that can contribute to greater asymmetries and undermine nuclear deterrence.
• Ensure inclusive dialogue by expanding the pool of actors in risk reduction efforts, including by engaging the private sector and industry.
• Intensify engagement with China to rebuild trust and develop normative frameworks around confidence-building security measures.
• Strengthen regional perspectives by utilizing existing frameworks and institutions to address destabilizing local factors, escalatory dynamics, and nuclear risks.
• Identify benchmarks that can further the operationalization of risk reduction and lay out clear goals and timelines for implementing measures.

Wan suggests that policymakers and experts need to see risk reduction as a priority. He asserts that risk reduction should be more untethered from notions of strategic stability and deterrence as these Cold War–era concepts no longer fully reflect the conditions of the current nuclear landscape. In the short term, he suggests that states work toward risk reduction unilaterally and in small groups of like-minded states. Some practical actions that these states may undertake include coordinating on risk assessments and implementing effective signaling to prevent external misperceptions and inadvertent escalation. Wan concludes by suggesting that cross-cutting discussions and confidence building efforts can make strengthening risk reduction possible.
 

“A Turn to Nuclear Counterproliferation: Consequences of a Deteriorating Nonproliferation Regime” by Doreen Horschig

In her essay, Doreen Horschig highlights the growing precarity of the global nuclear order amid the war in Ukraine and as concerns arise about nonnuclear states—particularly Iran, Japan, South Korea, and Saudia Arabia—acquiring nuclear weapons. She analyzes the traditional tools to prevent nuclear proliferation and explains that treaties, export controls, safeguards, extended deterrence, and economic sanctions have not always prevented states from pursuing independent nuclear weapons programs.

Given the limitations of the nonproliferation regime and current doubt about the effectiveness of negotiations, Horschig explores whether states resort to counterproliferation as an alternative to traditional nonproliferation. Counterproliferation strategies, she explains, tend to supplement nonproliferation efforts in disincentivizing the creation of nuclear programs and the use of nuclear weapons—particularly in East Asia, the Middle East, and in the Russia-Ukraine War. Such operations include the state-sanctioned use of force against nuclear materials, commodities, personnel, or infrastructure via military strikes, cyberstrikes, electronic warfare, assassinations, or sabotage.

Horschig highlights several empirical examples that warrant close attention and provides quantitative evidence for a novel trend of increased counterproliferation activity that is in its infancy. She argues that if the war in Ukraine causes an increase in calls for nuclear proliferation, counterproliferation incentives will grow alike, prompting an increased risk of escalation between actors due to the operations’ illegal nature and violation of sovereign rights.

Horschig highlights the need for an effective nonproliferation regime to counter nuclear escalation, promote transparency, and encourage trust internationally. She advises practitioners to continue implementing and strengthening traditional nonproliferation commitments but also to explore novel arms control approaches that address new technologies and manage multifaceted security risks. The United States, she suggests, should continue to strengthen extended deterrence assurances with Japan, South Korea, and its other allies.

Horschig’s essay underscores the urgency to prioritize the strengthening of the nonproliferation regime to prevent states from considering military operations or other counterproliferation strategies. She concludes by emphasizing that productive arms control negotiations are possible despite a shifting geopolitical landscape and technological advances. She stresses the necessity of negotiations, highlighting the potential calamitous consequences of neglecting efforts to work diplomatically toward nuclear nonproliferation.
 

This publication was supported by the Raymond Frankel Foundation as part of the American �����Ƶ’s project on Promoting Dialogue on Arms Control and Disarmament.