The nuclear doctrines of Ukraine, Belarus, and Kazakhstan—former nuclear weapons states (NWS) in the post-Soviet bloc—have significantly diverged. While the current nuclear doctrine of Kazakhstan is similar to other non-nuclear weapons states and focuses on advocating for nonproliferation, Ukraine's doctrine relies on nuclear guarantees and Belarus' on nuclear deterrence posturing. The motivation behind Ukraine's and Belarus's nuclear doctrines reflects their security vulnerabilities, including the ongoing War in Ukraine. However, the ability of these two states to achieve forward-positioned doctrines relies on two key factors: the support of nuclear weapons states and their unique status as former NWS. This article finds that former NWS may have a more significant impact on strategic stability due to their unique position in the international nuclear norms regime.
Introduction
The Budapest Memorandum has de facto ended, nearly three decades after Russia agreed in the memorandum to not attack Ukraine with nuclear weapons in exchange for Ukraine's denuclearization. On 24 February 2022—the day that Russia invaded Ukraine—President Vladimir Putin stated that Russia was "one of the most powerful nuclear states" and that any direct attacks or hindrance of Russian efforts would lead to a response "never seen" before.
1This rhetoric laid the foundation for subsequent nuclear escalation, notably including threats to utilize tactical nuclear weapons over Western intervention in Ukraine and the stationing of Russian nuclear weapons in Belarus.2 Such posturing positioned both Ukraine and Belarus at the center of global conversations on nuclear proliferation. However, it was hardly the first time that these post-Soviet countries had played a critical role in strategic stability.
With the collapse of the USSR in 1991, four newly-formed countries had nuclear weapons stationed within their territories: Russia, Ukraine, Belarus, and Kazakhstan.3 While Russia adopted the former USSR's status within the Nuclear Nonproliferation Treaty (NPT) as a Nuclear-Weapon State (NWS), the other three states signed the Lisbon Protocol in 1992, agreeing to join the NPT as Non-Nuclear-Weapon States (NNWS).4 Their accession to the NPT initiated a denuclearization process that lasted until 1996 and involved the transfer of more than 6,000 strategic and tactical nuclear weapons to Russia.5 In exchange for denuclearization, Ukraine, Belarus, and Kazakhstan joined the START I Treaty, where the United States and Russia agreed to limits on their nuclear arsenals.6 The three states also received security guarantees via separate but similar agreements under the 1994 Budapest Memorandum, where Russia, the United Kingdom, and the United States agreed to respect their territorial and political sovereignty, to not utilize nuclear weapons in those countries, and to respond if another country should break these obligations.7
However, the current War in Ukraine underscores the failures of the Budapest Memorandum: Russia has broken its commitment to not attack Ukraine and has threatened the use of nuclear weapons, while the United States and United Kingdom have been unable to effectively enforce their security guarantees. In fact, the lapse of this agreement has pushed Ukraine's nuclear doctrine further apart from those of Belarus and Kazakhstan. Since the 1990s, the internalization of varying security threats has led to differences in the nuclear doctrines of the three countries. While Ukraine's current nuclear doctrine focuses on its need for nuclear guarantees, Belarus's involves nuclear deterrence posturing and Kazakhstan's advocating for nonproliferation. And, as the nuclear doctrines of Ukraine and Belarus escalate further due to the War in Ukraine, so too does their impact on stability.
Former nuclear weapon states like Ukraine, Belarus, and Kazakhstan significantly affect strategic stability because their former status enables more escalatory nuclear doctrines than other non-nuclear weapons states. The current doctrines of these three countries therefore not only explicate how divergent their positions are, but also how varying security threats to state actors can contribute to the degree of their impact on global nuclear stability by weakening international norms. This article provides a critical analysis of the nuclear doctrines of the three countries, arguing that former NWS can have a greater impact on stability than other NNWS due to their increased ability to utilize escalatory practices with fewer negative consequences. The article suggests that former NWS are therefore a unique category of nuclear-related states that international norms must independently address.
Divergent Nuclear Doctrines in Ukraine, Belarus, and Kazakhstan
Nuclear doctrines for non-nuclear weapons states traditionally utilize strategies that advocate for nonproliferation and/or disarmament, request nuclear guarantees, posture nuclear deterrence, or proliferate nuclear weapons. While most NNWS focus on nonproliferation and disarmament, the least escalatory strategy, states can adopt nuclear doctrines that engage with any combination of these strategies as evidenced by the post-Soviet former NWS. In order of increasing escalation, the current nuclear doctrine of Kazakhstan focuses on advocating for nonproliferation, while Ukraine currently focuses on nuclear guarantees and Belarus on nuclear deterrence posturing. The motivation behind Ukraine's and Belarus's decision to maintain more forward nuclear doctrines reflects their past security vulnerabilities. However, the ability of Ukraine and Belarus to actually achieve their forward-positioning relies on two key factors: the support of nuclear weapons states and arguably their unique status as former NWS.
To begin with, Kazakhstan's nuclear behavior aligns with that of a "typical" NNWS: its nuclear doctrine is the only one of these three countries that remains entirely focused on nonproliferation, assisted by its position in the Central Asia Nuclear-Free Zone instead of sandwiched between Russia and NATO.8 Since independence, Kazakhstan's nuclear doctrine has primarily involved the aftermath of nuclear testing, as it served as one of the Soviet Union's major test sites.9 Not only did the United States assist Kazakhstan with removing enriched materials and sealing test sites in the decades following independence, but Kazakhstan also initiated a United Nations General Assembly resolution in 2010 to call for an International Day Against Nuclear Tests.10 Its focus on testing has entrenched Kazakhstan's nuclear doctrine in nonproliferation. As opposed to Ukraine and Belarus, Kazakhstan is thus neither considering nuclear proliferation nor currently concerned about its nuclear umbrella. Its commitment to de-escalatory practices thus diverges from Ukraine and Belarus because the country neither has the motivation nor the ability to maintain a forward nuclear strategy.
By contrast, Ukraine's nuclear doctrine is more forward-positioned, as driven by security vulnerabilities and variations in NWS support over time. Ukraine's doctrine can be categorized by three eras: security guarantees, uncertainty, and interest in nuclear guarantees. Following its independence in 1991, Ukraine focused on the security guarantees from its denuclearization process. Specifically, Russia had agreed in the Budapest Memorandum to not attack Ukraine unless acting "in self-defense" or in accordance with the United Nations Charter.11 Ukraine thus had a minimal nuclear security mindset, primarily demarcated by concerns over gradually increasing Russian aggression. This shifted in 2014 with the Russian annexation of Crimea, which raised new worries over the strength of the memorandum's security guarantees. While Russia directly violated the memorandum, the United States reneged on its unofficial promises to Ukraine that it would respond in the event of Russian aggression, because it could not risk a direct conflict with another NWS.12 The 2014 annexation therefore began a second era characterized by nuclear uncertainty, where the extent of nuclear security and territorial integrity risks were unknown. Some of this uncertainty ended with the start of the War in Ukraine in 2022. As Russian actions directly fueled nuclear escalation and engaged in unconstrained territorial violations, the Budapest Memorandum de-facto ended, arguably leading to Ukraine's third era.13
Ukraine's doctrine today appears to rely on nuclear umbrella guarantees to respond to Russia's increasingly forward-positioned nuclear strategy. The War in Ukraine exacerbated Russian concerns over the ability of its conventional forces to win a war, increasing its strategic reliance on nuclear weapons as a deterrent.14 In response, Ukraine's emerging nuclear doctrine is thus framed in two contexts: first, the importance of formalized nuclear guarantees to prevent Russian aggression and second, consideration of whether Ukraine made a mistake in denuclearization. The first context understands the failure points of the Budapest Memorandum and establishes Ukraine's current interest in joining NATO, which has a formal nuclear deterrence policy for its member states.15 Although the United States has previously suggested that it would respond to a nuclear attack in Ukraine, the lack of a formal guarantee is of concern to Ukraine due to the historic U.S. failure to follow through on informal commitments. The second context acknowledges Ukraine's critical need for a nuclear guarantee which, if an external body like NATO cannot provide, might lead to domestic proliferation.16 Ukraine's current consideration of re-nuclearization is thus typically framed to pressure NATO and the United States to provide nuclear guarantees.17 Calls from individuals within Ukraine for re-nuclearization have thus far not resulted in the negative consequences faced by other NNWS pursuing nuclear proliferation. This is likely due to Ukraine's stronger ethical credibility, because of its status as a former NWS who willingly denuclearized in exchange for security guarantees that have now been broken.
Finally, Belarus's nuclear doctrine involves increasingly proactive nuclear posturing, similarly relying on NWS support. Following its independence, Russia and Belarus launched an integration process that led to the 1999 establishment of a Union State between the two countries as a "single economic space," with "coordinated foreign and defense policy."18 A "Union State" indicated that Belarus had an unofficial nuclear guarantee from Russia, while maintaining its own status as a NNWS.19 However, the union concept was only loosely applied and Belarus notably maintained a neutral position during the 2014 annexation of Crimea.20 Its independence ended in 2020 when Belarusian President Aleksandr Lukashenko accepted monetary aid from Russia to squash mass protests against his regime.21 In exchange, Belarus began to more actively align itself with Russia, increasing its economic dependence and support. Closer relations better situated Belarus to aid Russia during the War in Ukraine, suggesting that the Russian nuclear umbrella did extend to it..22 The umbrella was confirmed in March 2023 when Russia announced that it would station tactical nuclear weapons in the country.23
Since then, Belarus has adopted a nuclear doctrine based on its own interests in deploying these weapons, although Russia alleges that it maintains control.24 In 2023, Belarus created an updated National Security Concept and military doctrine. The former document mentions nuclear weapons in the context of concern over the growing interest of other countries in Europe in proliferation.25 The latter document, which went into effect in 2024, discusses nuclear weapons for the first time in Belarus's military doctrine and is presumed to reference "preventive deterrence for potential adversaries from unleashing armed aggression against the Republic of Belarus."26 Interestingly, Belarus's current nuclear doctrine, although still relying on Russian weapons, therefore attempts to distinguish its own authority over the weapons in its territory. Belarus's proactiveness postures it closer to a NWS, which contributes to international debate over whether stationing weapons in Belarus breaches its commitments under the NPT.27 The ability of Belarus to pursue such an escalatory nuclear position relies heavily on NWS support from Russia, due to bilateral agreements that formalize this arrangement. In direct contrast to the informal U.S. commitments in Ukraine, such agreements enable Belarus to maintain an even more forward nuclear doctrine.
While Kazakhstan's nonproliferation stance assists with nuclear de-escalation, both Ukraine and Belarus therefore utilize forward-positioned doctrines that are arguably enabled not only by NWS support, but also by the status of the two countries as former NWS. In Ukraine's case, its former nuclear status enables an ethical position that circumvents international taboos about NNWS. An international norm that supports accession to the NPT as an NNWS is an implicit guarantee against nuclear attacks, a guarantee that was made explicit for Ukraine in the Budapest Memorandum in trade for its denuclearization.28 However, Russia's threats to utilize nuclear weapons in Ukraine de facto ended the agreement, which could serve as justification for Ukraine to re-nuclearize, because the international norm against threatening an NNWS with a nuclear attack has already been broken. Regarding Belarus, its former nuclear status further obscures the gray zone between stationing and proliferating nuclear weapons. As Russia claims to maintain control of the nuclear weapons, Belarus's current nuclear status is differentiated from when it had full control of its own nuclear weapons, including in terms of the nuclear policy language it uses. This enables Belarus to position itself as an NNWS with stationed nuclear weapons, although it pushes the bounds of NNWS nuclear doctrines. Status as former NWS therefore plays a critical role in the modern nuclear doctrines of Ukraine and Belarus, while still enabling divergence between their doctrines based on security motivations and NWS support.
Impact of Nuclear Doctrines on Strategic Stability
The nuclear doctrines of Ukraine, Belarus, and Kazakhstan provide useful implications for the impact of such doctrines on strategic stability. The variations in impact are elucidated by their basis in evolving nuclear legacies. "Nuclear legacy" is often discussed in academic literature in the context of Post-Soviet countries, referring to the modern-day security policies that result from Soviet-era nuclear policy.29 This article applies a broader definition: the impact of developing, posturing, stationing, testing, or deploying nuclear weapons within or by a state on its current security policies. Based on this definition, the nuclear legacies of the three countries initially derived from nuclear weapons at independence, followed by voluntary relinquishment of these weapons in trade for security guarantees. However, from this common starting point, the legacies then diverged with Ukraine experiencing nuclear threats, Belarus receiving a nuclear umbrella and stationed weapons, and Kazakhstan facing the aftermath of testing. The divergence suggests that nuclear legacies are not definable from a stationary point in time, but are rather evolving concepts that change based on geopolitical factors.
Understanding nuclear legacies as evolving underscores the divergent impact of these three countries' nuclear doctrines on global strategic stability, or on maintaining limited incentives for deploying nuclear weapons.30 Such stability is especially vulnerable to dependencies on nuclear weapons in security strategy. Specifically, current doctrines that increase the need for nuclear guarantees or that proliferate nuclear weapons expand the reliance of security strategy on these weapons, and this in turn encourages further proliferation.31 Uncertainty also reduces the likelihood of disarmament, as countries cannot predict associated long-term risks or their potential future need for nuclear weapons.32 In addition, due to the failures of the Budapest Memorandum, countries may also be less willing to accept unofficial nuclear guarantees. As nuclear doctrines diverge further, these vulnerabilities in strategic stability may increase, because maintaining stability is difficult in a progressively unpredictable and variable environment.33
With regards to Ukraine, Belarus, and Kazakhstan, their divergent nuclear doctrines thus unevenly affect global strategic stability. Kazakhstan's doctrine arguably has a positive, albeit limited impact on stability based on its interest in nonproliferation.34 However, responses in the other two countries demonstrate the increased escalatory effect of their nuclear doctrines when compared to other NNWS. As Ukraine's doctrine shifted from uncertainty to a keen interest in nuclear guarantees due to Russia's attacks, this validated the importance of nuclear umbrellas to NNWS security.35 In addition, the limited, but existent rhetoric within Ukraine surrounding re-nuclearization validates the importance of nuclear weapons to defending one's own territory. Coupled with the lack of negative consequences, this rhetoric further weakens the international norm preventing nuclear proliferation, although it does align with other norms protecting territorial sovereignty. Altogether, Ukraine's nuclear policy positions, especially conversations surrounding re-nuclearization, can inadvertently erode international systems that specifically protect against nuclear proliferation and use.
Meanwhile, Belarus's nuclear posturing directly raises concerns of proliferation by blurring the lines between NNWS with stationed nuclear weapons and NWS, and opens a pathway for other NNWS to similarly make use of nuclear weapons.36 Belarus's forward-positioned nuclear doctrine pushes the bounds of what is acceptable for an NNWS as compared to a NWS. While previous agreements like NATO have enabled NNWS to have stationed nuclear weapons, as well as a say in how these nuclear weapons could be used, NNWS within NATO have never publicly adopted nuclear posturing language within their domestic military doctrines, rather relying on the organizational doctrine. The differentiation between domestic and organizational strategies has so far served as a critical delineation between unacceptable and acceptable NNWS behavior. Although Belarus's doctrine may not be substantially different from NATO NNWS in practice, its method routed in independent statements similar to an NWS breaks norms surrounding NNWS nonproliferation.
The substantial impact that Ukraine and Belarus therefore have on international norms reflects how their status as former NWS enable a greater impact on nuclear stability. Their ability to weaken international norms with more limited repercussions exists in part because international decision-makers have already seen the worst-case scenario for these countries in terms of their nuclear proliferation and the current situation is deemed less serious. Such a mindset derives from great power states acting as offensive realist actors, who "prepare for the worst-case scenario when assessing other powers."37 As offensive realists, other state actors will consider the worst-case scenario for post-Soviet former NWS as re-nuclearization and anything short of that as less concerning. By contrast, a "worst-case scenario" is not the same for other NNWS, where many states would view a realistic scenario as NNWS simply threatening to develop nuclear weapons. The historic memory of other states therefore impacts the ability of countries like Ukraine and Belarus to affect strategic stability, by lowering the normative barriers that would typically prevent such countries from forward nuclear doctrines. The unique status of former NWS suggests that these states can have a greater impact on nuclear strategic stability than other NNWS counterparts.
Shaping International Norms and Policy Agendas
The noted linkage between nuclear legacy, doctrine, and stability is important as it provides the foundation for a framework to understand relevant strategy. The nuclear doctrines of Ukraine, Belarus, and Kazakhstan—and their impact on strategic stability—provide important real-world case studies for understanding and countering the long-term stability consequences of nuclear proliferation. Although the exact geopolitical consequences are uncertain, the ability of these countries to utilize a forward nuclear doctrine if they choose suggests that international norms preventing proliferation require strengthening and reaffirmation to specifically address former NWS countries. In addition, constraints on NWS behavior, as the key facilitators of such forward nuclear doctrines, are critically required.
As the War in Ukraine continues, we may have to wait for the outcome of ongoing talks to see how the changes in these doctrines might further illuminate their impact on strategic stability. The recent change in the U.S. leadership will unquestionably affect how these countries, especially Ukraine, amend their nuclear doctrines. While the second Trump administration may provide weaker NWS support to Ukraine than before, less NWS support could either shift Ukraine's nuclear doctrine back or increase calls within Ukraine for a domestic nuclear capability. Meanwhile, Belarus could understand the political change in the United States as signifying less NWS backlash to positioning itself in a more escalatory posture. Regardless, one aspect remains certain—the interplay between the former status of NNWS and the current positioning of NWS will shape the future of strategic stability.
In December of 2024, thirty years after the Budapest Memorandum, Russia claimed that its current aggression was in line with its obligations under the agreement.38 Ukraine criticized the original agreement as having failed to achieve effective international protections for the country.39 Reports emerged that the current U.S. White House removed the memorandum from its website to allegedly avoid criticism for not meeting its obligations in Ukraine.40 Regardless of who is responsible, the era of the Budapest Memorandum had now ended—and an era where the nuclear doctrines of the post-Soviet former NWS have a more significant impact on strategic stability is here.
About the Author
Janani Mohan is an experienced professional in policy and international relations. She is a PhD candidate and Gates Cambridge scholar at the University of Cambridge, writing on the security of nuclear energy facilities. Her prior experiences include collaborating with the United Nations Innovation Cell to monitor open-source data from the War in Ukraine, consulting with the United Nations Development Programme in South Africa to increase technology access for marginalized youth, and supporting the U.S. government on nuclear nonproliferation initiatives. She holds a Bachelor's degree from the University of California, Berkeley and a Master's in International Policy from Stanford University.
Footnotes
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