The Altered Nuclear Order in the Wake of the Russia-Ukraine War

A Turn to Nuclear Counterproliferation: Consequences of a Deteriorating Nonproliferation Regime

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Rebecca Davis Gibbons, Stephen Herzog, Wilfred Wan, and Doreen Horschig
Promoting Dialogue on Arms Control and Disarmament

Doreen Horschig

Is the global nuclear order beginning to unravel? Nuclear qualitative refinement and quantitative buildup have characterized recent developments in nuclear and ambitious nonnuclear states. Still, some observers point to the war in Ukraine as confirmation of the traditional nonproliferation regime’s resilience.1 Others are less optimistic. They note the dwindling of Cold War arms control measures; growing nuclear ambitions in South Korea, Iran, and Saudi Arabia; and efforts on the part of Russia and China to change the rules of the international order. Recent remarks on possible nuclear proliferation have intensified worries, however. Saudi Minister of Foreign Affairs Prince Faisal bin Farhan Al-Saud prominently stated in 2022 that, “if Iran gets an operational nuclear weapon, all bets are off,”2 and South Korean President Yoon Suk Yeol stated in early 2023 that Seoul “will introduce tactical nuclear weapons or build them” if North Korea’s nuclear threat grows.3 Proliferation concerns, tensions, and nearly two decades of stalled progress on nuclear arms control suggest that these traditional nonproliferation strategies have been weakened.

Where these strategies—including treaties, International Atomic Energy Agency (IAEA) safeguarding, and normative restraints—have had limited success, a vacuum to prevent proliferation has emerged. That is concerning because, as some argue, Russia’s invasion of Ukraine could trigger nuclear proliferation.4 At the Tenth Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), U.S. Secretary of State Antony Blinken stated that Russia’s behavior sends “the worst possible message to any country around the world that may think that it needs to have nuclear weapons to protect, to defend, to deter aggression against its sovereignty and independence.”5 Countries with latent nuclear capabilities and that have entertained the idea of an independent nuclear program are on the receiving end of this message.6

Fortunately, the Ukraine war might not trigger a proliferation cascade. Some argue that the outlook for further proliferation does not appear as pessimistic and that it might even strengthen U.S. nonproliferation efforts rather than ignite a cascade of new nuclear weapon states.7 Washington’s nonnuclear European allies are unlikely to pursue their own nuclear weapons programs. The U.S. security umbrella is more important than ever to these states, and an independent nuclear deterrent would not be of interest to the alliances. History has also shown that when a nuclear power threatens a weak state, as is the case in Ukraine, this does not automatically lead to proliferation. In addition, acquiring nuclear weapons is incredibly difficult, as it requires tremendous resources and causes resentment from the international community.

Despite the debate over the effect of the war in Ukraine on proliferation, the traditional nonproliferation regime has been challenged in the past few years—as another publication in this arms control series elucidates.8 In this paper, I discuss one consequence of a deteriorating nonproliferation regime and an alternative to the traditional arms control approach: counterproliferation. Counterproliferation here expands on Fuhrmann and Kreps’s work and is defined as the state-sanctioned use of force against materials, commodities, personnel, or infrastructure related to a nuclear weapons program that displays both a covert nature and strategic intent and employs nontraditional warfare.9 This can include limited military strikes, cyberstrikes, electronic warfare, assassinations, or sabotage to prevent or delay another country’s acquisition of nuclear bombs or its modernization of a nuclear program. This third option, or tertia optio, in the foreign policy toolbox is used when the first option, diplomacy, is ineffective and the second option, war, seems unwise. In line with Fuhrmann and Kreps, this paper excludes financial and economic sanctions from its definition of counterproliferation and focuses instead on the use of preventive force. Counterproliferation measures are often seen to complement coercive diplomacy by buying time for other punishment efforts to take effect, thus signaling resolve and managing escalation.10 This paper treats counterproliferation as a unilateral tool to prevent proliferation that countries might fall back to in the absence of diplomacy and a nonproliferation regime or doubt about the effectiveness of them.

I explore whether states resort to this third option when the failure of nonproliferation and arms control negotiations risks the second option, war. When do states resort to counterproliferation as an alternative or complement to traditional arms control, nonproliferation, and risk reduction to hinder quantitative and curb qualitative nuclear developments? I examine counterproliferation as a tool both to prevent new states from proliferating and to control nuclear buildup in existing nuclear states.

Concerns over nuclear proliferation are plausible—given the Russia-Ukraine war and an increasingly multipolar world in which different countries and models of government must compete for power and influence amid reemerging forces of fascism, authoritarianism, and imperialism—but should not be inflated.11 That threatened states may now consider proliferation given the war in Ukraine is in line with predictions made by proponents of security-driven rationales for proliferation.12 I examine current actors who are at risk of proliferating or who might use counterproliferation tools and find them to be useful. In contrast to the contributions by Rebecca Davis Gibbons, Stephen Herzog, and Wilfred Wan in this publication that explore two alternative paths to arms control and nonproliferation, this paper examines why these diplomatic paths are crucial in the first place. Some states might resort to counterproliferation as a more hawkish alternative. I investigate with open-source material whether counterproliferation activity has increased since the advent of the atomic bomb. My findings suggest that no major expansion in military action has occurred but that a premature trend toward such action can be discerned.

Counterproliferation operations are not yet a common tool to prevent proliferation. Nonetheless, several cases hint at increased covert activities. I identify these empirical examples that require attentive observation, and provide a brief quantitative evaluation of the trend in counterproliferation cases and an explanation of the risks of increased counterproliferation and the implications for the nonproliferation regime. I end the paper with recommendations for practitioners.

Academics and policy analysts alike have written plenty on the limitations of the nonproliferation regime, but few have explored what that means for state behavior when faced with opponents or allies interested in nuclear proliferation. This paper adds to efforts to close this gap by exploring whether states resort to counterproliferation strategies instead of pursuing more traditional paths of negotiations and extended deterrence. I explain why a turn to preventive force would likely increase the risk of escalation between countries. Premeditated attacks often violate sovereign rights and are seen as aggression—possibly even counterproductively incentivizing state proliferation. Those who were proliferating before because of security concerns might now be more interested in obtaining an independent deterrent in response to an adversary’s attack. The list of countries of concern—those that might proliferate or use military operations to prevent such proliferation—could grow. Policymakers should be looking for ways to disincentivize these destabilizing and dangerous military measures. The key policy recommendation of this paper is to preserve and build on traditional means of preventing proliferation without encouraging military measures. Current actors should be wary not only of the risk of additional nuclear powers but of the increased tensions that come from trying to prevent nuclearization through counterproliferation. This is a troubling state of affairs, with serious consequences for the risk of escalation.



Traditional Nonproliferation Tools

Traditionally, the global nonproliferation regime has used tools such as treaties, export controls, technology restrictions, and international safeguards to prevent countries from proliferating.13 The most well-known effort was the signing of the NPT in 1968. In its first fifty years, the treaty created some of the broader political context and moral pressure that led to the reduction of nuclear weapons. While the treaty did not prevent all nonnuclear states from obtaining nuclear weapons, the number of proliferators might have been much higher without the NPT. In addition to creating a widely accepted norm against nuclear weapons, the NPT’s comprehensive safeguards agreements (CSAs), implemented by the IAEA, have made nuclear inspections and safeguards a standard of moral state behavior. Furthermore, the IAEA’s “Additional Protocol” is an aspirational standard that provides more tools to verify the peaceful use of nuclear materials.14

However, the emerging multipolarity of the global nuclear order might present a significant test to the durability of the nonproliferation regime. The four salient elements that contributed to the NPT’s success—widespread membership, adaptability, enforcement, and fairness—are under scrutiny by a new order.15 The five nuclear states—China, France, Russia, the United Kingdom, and the United States (the P5)—were supposed to make “good faith” efforts to reduce and ultimately eliminate their nuclear arsenals. The NPT has been unsuccessful in enforcing this provision, which has created a rift among NPT members over the pace of disarmament, thus establishing the foundation for the Treaty on the Prohibition of Nuclear Weapons (TPNW) that bans the use, possession, testing, and transfer of nuclear weapons. The NPT also did not prevent proliferation in states such as India, Pakistan, Israel, and North Korea. The long-term prospect of the global nuclear order under the NPT regime depends on some level of buy-in from the great powers, including China and Russia.16 While the TPNW reiterates the norm against nuclear weapons, the effort has its limitations and is not curbing existing nuclear programs. States under nuclear umbrellas are not signing onto the treaty. In fact, despite a growing list of signatories, the TPNW has been widely condemned by nuclear-armed states and their allies.17

As the stress on the nonproliferation regime has become more visible, some have questioned the efficacy of the traditional approach and expressed grievances about the justice of nonproliferation enforcement, which arguably manages the status quo in the interests of the nuclear weapon states.18 This is not to say that the nonproliferation regime has been or is ineffective. Quite the opposite: few countries have proliferated, nuclear weapons have not been used to attack another country since 1945, and the number of nuclear warheads has been greatly reduced. Rather, progress seems to be stalling, especially with the waning of U.S. global influence. For decades, Washington used various tools, such as diplomacy, positive inducement, and coercion, to painstakingly build the nuclear nonproliferation regime and get states to adhere to it.19

In addition to the formal agreements, extended deterrence is an extension of this traditional nonproliferation and arms control approach—the commitment to deter and, if necessary, to respond across the spectrum of potential nuclear and nonnuclear scenarios in defense of allies and partners.20 This includes the U.S. nuclear umbrella over South Korea, Japan, and Australia, as well as the North Atlantic Treaty Organization’s (NATO) defense commitment to Canada and numerous European countries. Given the geopolitical tensions in several regions, some argue that the risk of allied proliferation is growing.21 Others downplay such worries by claiming that the war in Ukraine increases allies’ need for security alliances, thus forestalling efforts to pursue nuclear programs independently.22 While allies might be worried about their security and the credibility of U.S. commitments to their defense, in Europe at least, the United States and NATO have signaled their commitment to allies and partners since the beginning of the Ukraine war. This commitment to a credible nuclear umbrella for allies, however, can also undercut efforts to reduce the role of nuclear weapons or even to cap the U.S. nuclear arsenal in accordance with its NPT obligation.

Credible, extended nuclear security guarantees can also backfire when clients fear that their guarantors will drag them into nuclear conflict.23 Further, when such guarantees are not credible, support for proliferation in countries under extended deterrence will be high, and they may feel empowered by the nuclear umbrella to consider sheltered pursuit of nuclear weapons.24 Weak states under extended deterrence are more vulnerable to counterproliferation and therefore tend to be deterred from pursuing independent proliferation. However, strong protégé states under a nuclear umbrella are better able to shield themselves from such threats and are therefore more likely to nuclearize.25

Extended deterrence commitments can also highlight the inability of norm-enforcing measures, including the NPT, to prevent nuclear proliferation. South Korea, for example, received security assurances from its defense partner, the United States, when Seoul merely threatened to acquire nuclear weapons.26 In a joint declaration released in April 2023 (i.e., the “Washington Declaration”), the United States signaled its commitment to South Korea, including through “the upcoming visit of a U.S. nuclear ballistic missile submarine to the ROK” and the establishment of a new Nuclear Consultative Group (NCG) that, similar to the NATO Nuclear Planning Group, intends “to strengthen extended deterrence, discuss nuclear and strategic planning, and manage the threat to the non-proliferation regime.”27 Allies and partners are increasingly likely to seek greater protection from Washington by toying with a pursuit of the bomb to shore up security commitments.28 Thus, the NPT is not as important as coercive bargaining to thwart a latent nuclear country’s proliferation interests.29

Lastly, economic sanctions are another tool to punish countries that attempt nuclear proliferation. Sanctions have succeeded in deterring states from starting nuclear weapons programs.30 However, they have not been effective in stopping active nuclear weapons programs.31 Dozens of United Nations (UN) Security Council resolutions sanctioning North Korea and Iran have failed to halt those countries’ accelerating nuclear programs. The reimposed sanctions on Iran in 2018 had a reverse effect, causing Tehran to accelerate its nuclear program by enriching uranium to levels that breached the limits put in place by the Joint Comprehensive Plan of Action (JCPOA). While the effectiveness of economic and financial sanctions warrants a wider discussion, neither nonproliferation nor sanctions have been fully successful in halting the spread of nuclear weapons.

An alternative tool to the nonproliferation and sanctions regime is the use of military action to counter proliferation. New technologies and open-access information have lowered the entry barriers to a range of weapons systems that can be used for counterproliferation (including explosives, cyber weapons, low-tech drones, and guns assisted by artificial intelligence), simplifying efforts to conduct such operations.



Preventing Horizontal Proliferation

Horizontal proliferation describes the building of nuclear weapons in the traditionally understood manner. The term refers to states that do not have nuclear weapons but are seemingly acquiring or developing the capability and materials for their production. Proliferating states to watch closely include those with latent nuclear capabilities and heightened external security threats.32 Russia’s war against Ukraine has emphasized to these states that the global nuclear order can be a self-serving security hierarchy characterized by nuclear injustice.33 The nonnuclear states affected by this injustice might flirt more than ever with Kenneth Waltz’s notion that possessing one’s own nuclear weapons can preserve peace.34 Taking his argument that more nuclear powers means more stability due to the vigor of nuclear deterrence, nonnuclear countries might be enticed to proliferate. Some observers argue that the Russia-Ukraine war is indicative that nuclear deterrence is working.35 Out of fear of direct NATO involvement and nuclear use, Russia refrained from attacking NATO territory—including targets such as supply depots and logistics support. This logic seems to hold true for NATO as well, which has avoided direct involvement on the ground in Ukraine—likely because of Russian President Vladimir Putin’s nuclear threats.36

The Russia-Ukraine war suggests that nuclear proliferation and counterproliferation are two areas that warrant increased attention. First, if an argument can be made in favor of deterrence and nuclear weapons amid the war, countries with latent nuclear capabilities might choose to advance efforts to obtain their own nuclear deterrents rather than continue to rely on an extended deterrence regime with credibility issues. Nuclear deterrence has limited the escalation of the conflict in profound ways. Thus, some nonnuclear countries might seek a nuclear program for strategic stability if they perceive nuclear deterrence to have been a potent factor in Ukraine. Second, to avoid the dilemma of not being able to attack military targets (because those targets are in countries that possess nuclear weapons), some would-be antagonist states might see counterproliferation operations as an enticing means of preserving their own flexibility of movement. Following Russia’s example, states might want to prevent new nuclear actors as a way of keeping open the option of military confrontation. Other states that use covert counterproliferation operations might not want additional nuclear players in the global order because the accidental use of nuclear weapons and the risk of conventional, minor, and indirect conflicts increase with the number of nuclear states—also known as the stability-instability paradox.37

Middle East

Among the latent nuclear countries, Iran has been the most prominent proliferator, in part due to the absence of effective measures to halt or reverse its expanding nuclear enrichment program since the U.S. withdrawal from the JCPOA in 2018. A mutual return to compliance no longer seems feasible, and negotiations to stabilize the current nuclear crisis have stalled. An April 2023 letter to U.S. President Joseph Biden from prominent nuclear experts urged the administration to pursue a new diplomatic strategy.38 The reimposition of sanctions in 2018 led to the revival and expansion of Iran’s nuclear activities. Efforts to halt the Iranian nuclear program with conventional tools such as diplomacy, negotiations, and sanctions have reached a stalemate.

Counterproliferation operations have sometimes been used when diplomatic efforts fell short. Israel’s alleged counterproliferation strategy, which aims to prevent the nuclearization of Iran, represents the most prominent case of covert activities of this nature. Israeli officials have confirmed numerous times that the nation will not accept a nuclear-armed Iran. In August 2022, former Prime Minister Naftali Bennett stated that Israel “will utilize all available tools to prevent the Iranian nuclear program from advancing,” and, in February 2023, Israeli Defense Minister Yoav Gallant reiterated at the Munich Security Conference that “when we [Israel] speak of preventing Iran from gaining a nuclear weapon, we must keep all the possible means—I repeat, all possible means—on the table.”39 The United States has also signaled its willingness to go beyond diplomatic means to prevent a nuclear Iran, stating it would “never allow Iran to acquire a nuclear weapon.”40 The strong rhetoric has been bolstered by an increase in military action in the region.

Israel has allegedly engaged in counterproliferation through cyberattacks, sabotage, and assassinations since 2007.41 Some of the more prominent attacks include the assassination of senior nuclear scientists Majid Shahriari and Fereydoon Abbasi-Davani (in 2010), Mostafa Ahmadi Roshan (in 2012), and Mohsen Fakhrizadeh, “father” of Iran’s nuclear weapons project (in 2020); the sabotage of the Bid Kaneh and Natanz missile facilities; and a cyberattack using Stuxnet, a malicious computer worm, to destroy centrifuges used for uranium enrichment.42 The Mossad, Israel’s intelligence service, has a tradition of assassinating nuclear scientists who are important to the Iranian nuclear program as a way to spread fear among those who remain alive.43 More recently, Israel has allegedly used drones to attack military sites that develop nuclear technology, including in a June 23, 2021, attack on the Iran Centrifuge Technology Company near the city of Karaj, a strike on May 25, 2022, on the Parchin military complex, and dual January 28, 2023, strikes aimed at pro-Iranian militant groups in Syria and an Iranian military site in the city of Isfahan, home to one of Iran’s largest nuclear research centers.

Other incidents, such as the assassination of Roshan in 2012 and the 2020 sabotage of the Khojir missile facility are not with full confidence attributed to Israel, although the Mossad is alleged to have been involved. In 2022, four more Iranian officials died under unresolved but suspicious circumstances that suggest Israeli involvement, including Ayoob Entezari and Kamran Aghamolaei, two Iranian scientists working at a military research center, who fell ill and died in May 2022. Israel is suspected not only of targeting senior but now also junior scientists.

The attacks on the Iraqi and Syrian nuclear reactors in 1981 and 2007, respectively, show that Israel is willing to go beyond assassination and sabotage to use airstrikes to prevent an adversary from obtaining nuclear weapons.44 Israel is not alone in signaling its readiness to use military action. With diplomacy in crisis, “Washington and Jerusalem are already discussing a ‘Plan B’ if a diplomatic settlement remains beyond reach. This path would place Iran and the United States on a collision course—as well as exacerbate sectarian tensions, deepen societal divisions, and trigger new conflicts from the Levant to Afghanistan.”45

The reoccurring attacks are especially dangerous because the tensions between Israel and Iran run so high and are further intensified by the ongoing war in Gaza between Israel and the Iranian-backed terrorist organization Hamas.46 The Council on Foreign Relations rates an Israel-Iran military confrontation over Iran’s nuclear program as a top-tier 2023 risk.47 The shadow war between Israel and Iran has intensified, and Israeli counterproliferation efforts could push the conflict further into the open. The fragile stability in the region is challenged by the increasingly close relationship between Iran and Russia, adding to the risk of escalation. That is, a conflict between Israel and Iran could become a proxy war between the United States and Russia.

Adding to the complexity of covert operations, not all attacks on Iran’s nuclear program are limited to external actors. In October 2022, Iranian hacking group Black Reward stole information from the Atomic Energy Organization of Iran.48 Just as governments have turned to private contractors for espionage, they can also outsource spyware, such as Pegasus’s ForcedEntry security exploit, and commission cyberattacks to gain information about a nuclear program.49 Attacks carried out independently by third parties can also heighten the risk of accidental escalation if the perpetrators are misidentified. Iran, for example, might accuse Israel of carrying out a cyberattack perpetrated by a third party (or of hiring that third party to carry out the attack) and retaliate in response.

Like Israel, Saudi Arabia has also made its nuclear intentions clear. Should the Persian archrival go nuclear, Saudi Minister of Foreign Affairs Prince Faisal bin Farhan Al Saud warned in 2022, “all bets are off.”50 The kingdom would develop nuclear weapons, and the nuclear dimension of Persian Gulf politics would be in flux. Saudi Arabian Crown Prince Mohammed bin Salman confirmed this objective to Fox News in September 2023.51 Some red flags can be identified, including the Saudi refusal to sign the gold standard “123 Agreement” with the United States that would prevent the kingdom from enriching domestic uranium and reprocessing spent fuel.52 Saudi Arabia has also not yet fully committed to abide by strict international safeguards at its first nuclear site, and it did not sign a CSA with the IAEA to allow the nuclear watchdog to inspect for undeclared nuclear activities. Further, the country is now manufacturing ballistic missiles. Lastly, the kingdom has asked the United States to help—and already received help from China—with uranium enrichment and other elements of its nuclear program. Some observers fear that the kingdom’s recent pattern of behavior suggests that its civilian, peaceful intentions might change in the future.

Saudi Arabia does not yet, however, have a substantial nuclear infrastructure, although pathways to enrichment technology could be found with Chinese help. A small nuclear research reactor at the King Abdulaziz City for Science and Technology on the outskirts of Riyadh remains under construction. Whether the country’s refusal to sign the “123 Agreement” indicates a proliferation risk is a matter of debate.53 The gold standard would prohibit the kingdom from developing any type of enrichment technology, but, if it were to sign the agreement, it might feel compelled to violate it by secretly building a small fuel enrichment plant if Iran proliferates further. Saudi Arabia has also turned to Washington to broker diplomatic relations between the kingdom and Israel and to provide other security guarantees beyond nuclear deterrence.54 In addition, China has played an increasingly important role as peacemaker between the kingdom and Iran. Riyadh, rather than obtaining its own nuclear deterrent, has looked to other security assurances to boost its defense. Thus, the scale of Saudi Arabia’s nuclear ambitions remains a matter of conjecture. While critical infrastructure in Saudi Arabia has been hit by cyberattacks, including a petrochemical plant in 2017 (by Russian hackers), and kinetic attacks (e.g., drone strikes), including a 2019 attack on oil processing facilities (by Iran and the Houthis), no incidents of (or plans for) external interference with Saudi nuclear installations are known. The Russian cyberattack, however, emphasized what is possible. In the face of active nuclear programs in both Iran and Saudi Arabia, Israel would surely amplify its counterproliferation strategy, which it allegedly admitted to in September 2023.55

Another player in the Middle East has made ominous comments about obtaining its own nuclear deterrent, which would challenge its obligations and commitments under NATO. Turkey believes it has the right to develop nuclear weapons for defensive purposes. In 2019, Turkish President Recep Tayyip Erdoğan expressed his frustration with the global nuclear order, suggesting that Turkey should not be forbidden from obtaining nuclear weapons.56 However, concerns over Turkey’s proliferation have been largely exaggerated. As soon as Turkey signed an agreement with Russia on nuclear cooperation in 2010, proliferation concerns were raised. In April 2023, Turkey received its first shipment of nuclear fuel as part of this agreement. While some argue that Ankara is one of the more likely latent nuclear sites to use its nuclear energy program for malicious purposes, its nuclear plant is operated by a third party, Rosatom, and Turkey has no direct access to nuclear material and therefore no way to divert it.57 Of course, the intentions of Turkey’s leadership cannot be as effectively measured as current capabilities because elites might not reveal all that they are thinking. Turkish interest in a nuclear weapons program might have grown over the years. Two wars in its geographical proximity are likely not reducing the interest in a stronger defense posture. Turkey, especially its inscrutable leader, should be watched closely. Tel Aviv and Washington would likely consider using all tools at their disposal—including diplomatic pressure and counterproliferation strategies—to prevent either Saudi Arabia or Turkey from obtaining nuclear weapons.

Climate change and concern over energy security are likely to inspire further expansion of nuclear power in the Middle East over the next few years. The UAE, which already has an operable nuclear power plant, recently commissioned a fourth reactor.58 Egypt began construction of its first nuclear power plant in July 2022.59 Jordan has shown interest in small modular reactors and uranium extraction and mining. All of this activity has been used for peaceful purposes and fully adhered to international safeguards, but regional security concerns and a nuclear Iran could affect that balance. Further, counterproliferation operations do not necessarily need to be “justified” by those employing the strategy. Suspicion alone can be used to rationalize counterproliferation efforts, even against nuclear programs that are subject to safeguards—which can have limitations.

South Korea and Japan

With China advancing claims in the East China Sea and North Korea increasing its nuclear and missile capabilities, Japanese and South Korean calls for domestic nuclear weapons programs are amplifying. In Japan, several politicians—many within the Liberal Democratic Party—have spoken positively about becoming a nuclear weapon state despite their nation’s long tradition of rhetorical ambivalence on the matter.60 Putin’s nuclear threats have made the domestic debate about a Japanese nuclear deterrent more urgent.61 Similarly, some South Korean elites have called for nuclear proliferation to deter an invasion by North Korea.62 President Yoon expressed willingness to consider the introduction of tactical nuclear weapons if North Korea’s nuclear threat grows.63 While President Yoon’s statements may have been a bargaining strategy designed to elicit stronger security commitments from the United States, some experts warn that the domestic nuclear trajectory may be difficult to reverse. Debate over a South Korean nuclear deterrent is proceeding.64 Elites in both countries have long been empowered with resources to sustain small-scale work on nuclear engineering, thereby maintaining that knowledge base.

The increasing threat perception of China and North Korea has shifted public sentiment in South Korea and Japan. Greater than 70 percent of the South Korean public now supports a nuclear weapons program but not the use of nuclear weapons.65 The war in Ukraine has had a large effect on sentiments in Japan, where the public—although less supportive of an independent nuclear program than South Koreans—has begun to question the U.S. security commitment.66 Survey respondents fear both alliance abandonment and entanglement, either of which can lead to support for proliferation in countries under extended deterrence when security guarantees are not perceived to be credible.67 As domestic barriers to nuclear weapons have been lowered by thought leaders through the cultivation of new attitudes and even broad support, the political costs of backing down over nuclear issues in negotiations have increased.68

The Ukraine-Russia nuclear weapons dimension is making the public and elites in South Korea take North Korea’s nuclear threat seriously. The realist perspective would suggest that indigenous nuclear programs should be pursued to deter adversaries from mirroring Russia’s invasion. Both Japan and South Korea are strong protégé states that can shield themselves against certain counterproliferation threats, which would hence not be effective in deterring a decision to nuclearize.69 Both countries are embarking on a major military buildup. For now, South Korea is looking to strengthen its ties with NATO.70 President Yoon attended the NATO summit in Vilnius in July 2023, signaling closer coordination between the alliance and South Korea. The Washington Declaration similarly confirms cooperation among the allies. However, South Korean conservatives and progressives alike have criticized the agreement, and disputes have emerged over the purpose of the NCG.71

Japan, following the G-7 Hiroshima Summit in May 2023, has continued to maintain its strong position of advocating disarmament. However, Tokyo is also looking for more protection from its allies. Some government officials are questioning the credibility of U.S. assurance. According to Ground Self Defense Force Lieutenant General (retired) Hirotaka Yamashita, there are “growing concerns among those involved in Japanese national security that the US might not actually come to help Japan when it comes down to it.”72 Former Prime Minister Shinzo Abe suggested nuclear sharing arrangements, hinting at an increasingly pro-nuclear stance in response to the Russian invasion of Ukraine.73 His posture did not encompass a desire for Japan to have independent nuclear weapons, but it could activate a larger debate. A risk factor that might lead to indigenous nuclear programs in Seoul and Tokyo is the use of Russian tactical nuclear weapons. If Russia used a nuclear weapon, South Korea and Japan would surely ask whether North Korea or China might also be emboldened to do so and would thus likely take a close look at their own defense and nuclear capabilities.

Given geographical proximity, the U.S. alliance, and Seoul’s 2022 updated military operational plans, China and North Korea have a strong national security interest in preventing South Korea and Japan from going nuclear. If South Korea were to move toward a nuclear weapons program, however, its regional adversaries—China and North Korea—would likely take active steps to prevent a new nuclear power in the Asia-Pacific. One option would be to use cyber capabilities, which both countries have shown they possess. China’s cyber defense has become proactive—more preemptive and offensive—as signaled during the Tianfu Cup International Cybersecurity Contest.74

Such cyber counterproliferation operations are not common but they are also not new in the Asia-Pacific—North Korea attacked the Korea Atomic Energy Research Institute, South Korea’s nuclear research body, in 2021, and in 2014 the Japanese Monju Nuclear Power Plant was infected with malware.75 In the first instance, the hacker group Kimsuky (affiliated with North Korea’s Reconnaissance General Bureau spy agency) targeted South Korea’s largest think tank studying nuclear technology. What information the hackers obtained is unclear. In the second case, the malware attack stole—and released online—a significant amount of data from the power plant’s control room.

Washington’s efforts to organize a strong, unified response to the Ukrainian invasion have likely reassured South Korea and Japan that the United States would also fulfill its defense commitments to them. However, if security dependence on the United States is questioned or weakened—or should Washington fail to demonstrate a forceful response if China moves against Taiwan—both Japan and South Korea may seek strategic autonomy through nuclear weapons. The risk of Asia-Pacific escalation would then increase tremendously. In April 2023, Washington signaled to South Korea the intensity of the American commitment to defend the country by promising to deploy nuclear-armed submarines in the South’s territorial waters for the first time since the 1980s.



Conclusion and Policy Implications

In this paper, I have explored whether states consider counterproliferation to be an alternative to traditional arms control and nonproliferation efforts to hinder qualitative and quantitative developments in nuclear programs. An analysis of current empirical examples of possible proliferators and activities by counterproliferators found no major expansion in counterproliferation operations. However, the quantitative data suggest that a new trend of increased activity may be in its infancy and that, while counterproliferation operations are not yet a common tool to prevent proliferation, several cases warrant attention. If proliferation or calls for proliferation increase specifically because of the Russian invasion, so, too, will counterproliferation incentives. This in turn would increase the risk of war because of retaliatory action or nuclear accidents (e.g., if counterproliferation attacks on nuclear facilities go awry).

An effective nonproliferation regime to stabilize the current escalatory spiral is crucial. Prioritizing transparency, negotiating IAEA access to nuclear sites in nuclear and nuclear-ambitious countries, and creating time and space for talk and negotiations should be at the forefront of the diplomatic toolbox as officials work to prevent qualitative and quantitative nuclear proliferation. Because of the current crisis of nuclear arms control, leaders should explore pathways that could lead back to the precrisis track of reducing existing nuclear arsenals and preventing nuclear ambitions in nonnuclear states.

To avoid further escalation, officials should continue to revive traditional nonproliferation approaches and alternatives (for more on this, see the other papers in this publication). On the current trajectory, 2026 will mark the first year since 1972 with no substantive nuclear arms control treaty. Several analysts see no future in traditional arms control agreements to curb existing programs and new proliferation. However, existing frameworks should not be completely disregarded, as they offer many lessons. Furthermore, an agreement to limit intermediate-range missiles (similar to the 1987 Intermediate-Range Nuclear Forces Treaty) is in the interest of all three major powers—Russia, China, and the United States. The ratification of any effective, verifiable treaty by Congress will face domestic challenges, but that does not mean the attempt should be abandoned. Any formal treaty will have to have bipartisan support. An alternative approach could be the development of frameworks that do not require congressional approval, such as presidential nuclear initiatives.

More recent approaches, such as integrated, cross-domain, asymmetric, and behavioral arms control that address new technologies of nuclear weapon states and manage multifaceted security risks to enhance stability, should also be considered.101 The TPNW has not been effective in restricting nuclear states’ modernization but can play an important role in reinforcing the norm against the possession and use of nuclear weapons among nonnuclear states that have shown no interest in proliferation. Further, bilateral agreements barring countries from attacking nuclear installations are another option worthy of policy consideration. A good example of this is the 1988 nonnuclear aggression agreement between India and Pakistan.102

U.S. policymakers should consider whether such agreements are possible between other countries, such as Israel and Saudi Arabia, where Washington is already taking the role of a mediator. If such negotiations are at too early a stage to include nuclear aspects, diplomatic discussions and meetings to improve relationships between adversaries may also help to reduce proliferation incentives. For example, Washington’s complex nonnuclear diplomatic talks with Israel and Saudi Arabia, if successful, could lower Riyadh’s threat perception and further avert nuclear ambitions in the kingdom.

Extended deterrence for Japan and South Korea should also be strengthened to avert their nuclear ambitions. A commissioned Chicago Council report suggests the creation of an Asian Nuclear Planning Group that jointly discusses U.S. nuclear planning and forces. 103 This could build on the intensified U.S. assurances and newly established NCG between South Korea and the United States under the Washington Declaration, but extend to include additional Asian players.104 Such a group would increase transparency and trust among U.S. allies and reduce a perceived need for their own domestic deterrent. However, signaling credible commitment is a notorious, age-old concern of the nonnuclear states protected by these umbrellas. If U.S. extended deterrence in Europe shows the smallest crack during the war in Ukraine, then the calls for independent nuclear programs in South Korea and Japan are likely to get louder. Both countries need a continuous signal that they will be worse off if they proliferate, because proliferation would lead to the loss of U.S. protection. Some have suggested the redeployment of U.S. tactical nuclear weapons and anti-ballistic missile systems on South Korean soil. Instead of deploying them, the United States could signal its commitment by discussing plans with Seoul to deploy them quickly if needed.

Any uncertainty about the effectiveness of the nonproliferation regime could increase incentives for states to consider military options. Further, in response to an adversary’s nuclear program, a state might launch a counterproliferation military strike if it perceived such a preventive war to be less costly than the consequences of its own proliferation.105 Despite stalled progress on arms control and nonproliferation, a preference for negotiations could grow stronger and provide an opportunity for a new diplomatic approach because of the shifting geopolitical landscape combined with technological advances. Options in nuclear countries and with possible proliferators are not ideal, but interim gesture-for-gesture agreements with informal sets of measures might be possible. Even a Russian nuclear attack against Ukraine might lead to more calls for arms control and disarmament.

If no effective efforts are made in this new era to prevent qualitative and quantitative nuclear proliferation, disarmament and nonproliferation efforts will be two more casualties of the Russia-Ukraine war and other global tensions. As a result, the risk of counterproliferation becoming the new toolkit to prevent proliferation will only increase. Open-source information suggests that only the United States, Israel, Russia, China, and North Korea follow an active nuclear counterproliferation policy and consider preventive force a viable instrument to hinder nuclear proliferation. However, with a weakened nonproliferation regime and lower entry barriers to counterproliferation operations, the number of actors using such strategies could increase. Actors should be wary not only of the risk of another nuclear power but the increased tensions that come from trying to prevent nuclearization through counterproliferation. This is a troubling state of affairs with serious escalation consequences.

Further research should examine U.S. willingness to resort to covert operations when allies or partners show an interest in their own nuclear deterrent. As evidence and speculation increase that others are using counterproliferation operations to prevent nuclear programs, the United States might also resort to such measures. Historically, when U.S. allies have shown interest in proliferation, Washington has used several strategies and tools to keep them in check, such as reminding them of their commitment to the NPT and offering security guarantees and defense commitments, as well as more hawkish approaches, such as threatening to withhold commercial nuclear technology.106 The United States has demonstrated its willingness to take coercive steps. How far it is willing to go warrants closer analysis.



Acknowledgments and Disclaimer

For helpful comments and suggestions, I thank Rebecca Davis Gibbons, Stephen Herzog, Tristan Volpe, and Wilfred Wan. I also thank the American Academy of Arts and Sciences for insightful suggestions and guidance. The views expressed and the analysis contained in the paper do not necessarily reflect those of the Center for Strategic and International Studies or the Project on Nuclear Issues. All remaining errors are mine.