Promoting Nuclear Disarmament through Bilateral Arms Control: Will New START Extension Pave the Path to Disarmament?

ABSTRACT

The United States and Russia agreed to extend the 2010 New START Treaty in February 2021. Many analysts believed that this step would reinvigorate the US-Russian arms control process, lead to deeper reductions in nuclear weapons, and possibly pave the path to nuclear disarmament. However, the United States and Russia might find it difficult to agree on an agenda for the next round of arms control negotiations, and neither may be willing to accept deeper reductions in their numbers of nuclear weapons. Changes in the international security environment, stresses in the US-Russian relationship, and increases in the size and scope of China’s nuclear arsenal may all impede progress. As a result, the next steps in arms control may focus on transparency, communication, norms, and risk reduction measures, both as a way to mitigate the risk of nuclear war and to, possibly, create the conditions needed for further reductions in the future.

KEYWORDS:

• Arms control
• disarmament
• risk reduction
• New START

Extending New START

On 21 January 2021, just 24 hours after taking office, the Biden Administration announced that it would pursue a five-year extension of the 2010 New Strategic Arms Reduction Treaty (New START). The United States and Russia exchanged diplomatic notes finalizing this extension on 3 February 2021, two days before the treaty was due to expire. This prompt policy choice capped off years of uncertainty about the future of bilateral nuclear arms control, with the Trump Administration first disparaging the treaty (Gertz 2019), then seeking, but failing to conclude an agreement for a limited extension during its last year in office.

Like the Trump Administration before it, the Biden Administration has advocated for a more expansive arms control process beyond New START. In a statement released after the February 3 extension, Secretary of State Antony Blinken noted that

President Biden has made clear that the New START Treaty extension is only the beginning of our efforts to address 21st century security challenges. The United States will use the time provided by a five-year extension of the New START Treaty to pursue with the Russian Federation, in consultation with Congress and U.S. allies and partners, arms control that addresses all of its nuclear weapons. We will also pursue arms control to reduce the dangers from China’s modern and growing nuclear arsenal. The United States is committed to effective arms control that enhances stability, transparency and predictability while reducing the risks of costly, dangerous arms races (Blinken 2021).

Expectations after Extension

Some who praised President Biden’s decision to extend the Treaty saw it as a way to reinvigorate the arms control process. Extension would retain limits on US and Russian strategic nuclear weapons and sustain the monitoring and transparency mechanisms that provided insights into the capabilities of those weapons. Many also expected the United States and Russia to move quickly to negotiate a follow-on agreement that achieved broader goals, including deeper reductions in the numbers of deployed nuclear weapons, limits on Russia’s new types of strategic delivery systems, and limits on warheads deployed on shorter-range nonstrategic delivery systems.

Some advocates of nuclear disarmament reached beyond these expectations to the hope that the extension would pave the way for a process of step-by-step reductions on the path to a world free of nuclear weapons. They believed that this was the path that President Barack Obama had endorsed in his speech in Prague in 2009 and the path required of all nuclear weapons states under Article VI of the Nuclear Nonproliferation Treaty (NPT).

This article reviews the recent history of US-Russian nuclear arms control negotiations and assesses the prospects for future progress in nuclear reductions. It concludes that these negotiations, even if they occur during the Biden Administration, may neither reach agreement on a treaty to follow New START nor mandate deeper reductions in US and Russian nuclear weapons. More generally, it seems unlikely that these discussions will launch a process that leads to the eventual elimination of nuclear weapons.

Recent US Policy on Arms Control

President Barack Obama appeared to link US-Russian arms control to the step-by-step reduction of nuclear weapons and the broader goal of nuclear disarmament when, in his speech in Prague, he stated “clearly and with conviction America’s commitment to seek the peace and security of a world without nuclear weapons”. He followed this aspiration by noting that the United States and Russia would negotiate a new Strategic Arms Reduction Treaty “to reduce our warheads and stockpiles”. According to President Obama, this treaty would “set the stage for further cuts, and we will seek to include all nuclear weapons states in this endeavor” (Obama 2009).

President Obama added two caveats to this commitment, noting, first, that “This goal will not be reached quickly – - perhaps not in my lifetime”. He also pledged to maintain the US nuclear arsenal, albeit at reduced numbers, noting that “As long as these weapons exist, the United States will maintain a safe, secure and effective arsenal to deter any adversary, and guarantee that defense to our allies”. Nevertheless, many advocates for disarmament took hope from this speech, and analysts sought to translate it into an agenda for progress towards a world free of nuclear weapons¹

The US-Russian arms control process did not, however, advance along this path. The New START Treaty mandated only modest reductions. The next round of talks, endorsed by Presidents Obama and Medvedev in July 2009, never materialized. As soon as New START entered into force, Russia’s Foreign Minister Sergei Lavrov seemed to question whether it was the first step towards deeper reductions, noting that Russia would not want to pursue further negotiations until New START had been implemented and that “further progress in nuclear arms reductions is possible only on a multilateral basis” (Lavrov 2011). He also offered a list of issues that the parties would need to address before moving forward with deeper reductions, including ballistic missile defense, strategic conventional arms, and weapons in space.

President Obama sought, again, to engage Russia in further reductions in nuclear weapons in a speech in Berlin in June 2013 (Obama 2013). As he had in Prague, he endorsed the long-term goal of disarmament, noting that “peace with justice means pursuing the security of a world without nuclear weapons – no matter how distant that dream may be”. He also announced that, after a comprehensive review, he had “determined that we can ensure the security of America and our allies, and maintain a strong and credible strategic deterrent, while reducing our deployed strategic nuclear weapons by up to one-third”. He specified that he would seek to negotiate these reductions with Russia “to move beyond Cold War nuclear postures”. In addition, he indicated that he would “work with our NATO allies to seek bold reductions in U.S. and Russian tactical weapons in Europe”.

This proposal did not, however, alter the trajectory of US-Russian arms control or spur progress on nuclear disarmament. A wide range of issues, including the Russian annexation of Crimea and occupation of Eastern Ukraine in 2014, US concerns about Russian noncompliance with the Intermediate-Range Nuclear Forces (INF) Treaty, Russia’s belligerent behavior and the increase in hazardous military incidents around Europe, and the changing political environment in the United States all combined to undermine support for negotiated, or even cooperative, efforts to limit US and Russian nuclear weapons.

The Trump administration initially argued against extending New START, and suggested that it should, instead, be replaced with an agreement that limited China’s nuclear weapons and all types of Russian nuclear weapons (Ford 2020). This approach was more likely to disrupt than advance arms control, as Russia and China rejected this formula. Even though the Trump Administration eventually fell back to a less ambitious approach, linking a one-year extension of New START to a one-year freeze on US and Russian nuclear stockpiles, it failed to conclude an agreement.

The Biden Administration seems to, again, be seeking a cooperative path forward on arms control. At their summit meeting in June 2021, President Biden and Russia’s President Vladimir Putin agreed that the United States and Russia would engage in “an integrated bilateral Strategic Stability Dialogue” that would “seek to lay the groundwork for future arms control and risk reduction measures” (White House 2021a). In his press briefing following the summit, President Biden noted that this dialogue would allow diplomats “to work on a mechanism that can lead to control of new and dangerous and sophisticated weapons that are coming on the scene now that reduce the times of response, that raise the prospects of accidental war” (White House 2021b). US and Russian officials met in late July 2021 to begin these talks and held a second plenary session in late September 2021 (Zargham and Lewis 2021).

Prospects for Progress in Arms Control

Setting an Agenda

In early September 2021, Bonnie Jenkins, the US Under Secretary of State for International Security and Arms Control, outlined the emerging US agenda for the future of arms control (Jenkins 2021). In her prepared remarks she indicated that the United States would re-emphasize the importance of effective arms control and risk reduction measures as a part of its effort to “reduce nuclear tensions and diminish the danger of a nuclear miscalculation or conflict”. She outlined several elements of the US approach to arms control with Russia:

First, we will look to capture new kinds of intercontinental-range nuclear delivery systems. Second, we will seek to address all nuclear warheads, including those which have not been limited previously, like so-called non-strategic nuclear weapons. Third, we will seek to retain limits on Russian intercontinental-range ballistic missiles, submarine-launched ballistic missiles, and heavy bombers equipped for nuclear armaments after New START expires in 2026.

Russia’s view of the preferred agenda is quite different from the US view. Foreign Minister Lavrov has noted that Russia would like the talks to cover everything that “influences strategic stability”, including “nuclear and non-nuclear weapons, offensive and defensive weapons”.² As has been the case since the two countries signed New START, the specific list includes ballistic missile defense, long-range strategic conventional arms, and weapons in space. Amplifying this point, Sergey Ryabkov, Russia’s Deputy Foreign Minister, noted that the US agenda outlined by Under Secretary Jenkins seemed “fragmentary”, making it “difficult to deduce a security equation that suits both sides” (Chernenko 2021). Ryabkov specifically rejected the US call to limit the warheads for shorter-range, or nonstrategic, delivery vehicles. He said that it is an “absolutely far-fetched artificial formulation of the question”. He noted that the difference between US and Russian geography “is so fundamental that attempts to draw parallels between the situation in which the United States itself is in and which we find ourselves in the context of non-strategic nuclear weapons is just a road to nowhere”.

The diverging views on what should be on the agenda do not necessarily preclude progress in beginning or concluding arms control negotiations. They do, however, indicate that the negotiations could be time-consuming and complex. The absence of parity, or even equivalence, among the capabilities placed on the table could generate the need for creative and often asymmetric trade-offs between and among priorities³ Even if the parties decide to separate the issues into different negotiating tracks, linkages between and among the tracks could complicate efforts to reach agreement.

Pursuing Reductions

In the absence of an agreement on the agenda for future arms control negotiations, some analysts have suggested that the United States and Russia focus, in the near term, on efforts to reduce the numbers of warheads permitted in New START. They could either seek to amend the Treaty to lower the legal limits, thus initiating a new ratification process in the US Senate, or they could announce through a joint statement between the Presidents that they would accede to the lower limits without a legally binding obligation. This could serve as an interim first step that would allow the parties to retain the predictability and transparency of New START and advance the goal of reducing the numbers of deployed nuclear weapons while they pursue negotiations on a subsequent treaty.

Some have cited President Obama’s speech in Berlin in 2013, when he announced that he would engage Russia in discussions to further reduce their deployed warheads below New START levels, as a model for this approach. As Rose Gottemoeller, the US negotiator for New START, noted in a recent article:

In 2013, the Joint Chiefs of Staff of the United States indicated their view that up to a one-third further reduction in operationally deployed strategic warheads could be taken without effect to US security. The United States proposed it at the time to the Russians, but there was no interest. If renewed, such a proposal would reduce US and Russian operationally deployed strategic nuclear warheads to approximately 1,000 on each side (Gottemoeller 2020).

This approach, however, overlooks security concerns that have altered the environment for nuclear arms control since 2013. The relationship between the United States and Russia began to change following Russia’s annexation of Crimea, its continuing aggression against Ukraine, and other concerning military activities around Europe (Kulesa, Frear, and Raynova 2016). Moreover, Russia continued to modernize its nuclear forces, and to introduce weapons systems that would not count under the limits in New START. The United States also determined that Russia had violated the 1987 Intermediate Range Nuclear Forces (INF) Treaty with its development of a new ground launched cruise missile, leading the Trump Administration to point out, in the 2018 Nuclear Posture Review, that “progress in arms control is not an end in and of itself, and depends on the security environment and the participation of willing partners”. It emphasized that neither of these conditions existed when Russia was violating arms control agreements and attempting to “change borders and overturn existing norms” in Crimea and eastern Ukraine (US Department of Defense 2018, 73).

Reports about the scale and scope of China’s nuclear modernization program have also recast assessments of the security environment. China has diversified its nuclear delivery systems and has begun construction of large numbers of new missile silos (Office of the Secretary of Defense 2020, 38–39; Osborne 2021). While China’s number of deployed nuclear warheads continues to fall far short of the numbers permitted under New START and deployed by the United States and Russia, US officials have begun to emphasize that China seems poised to double or even triple the numbers of warheads in its force by the end of the decade.

In 2013, President Obama said that the Joint Chiefs had determined that the United States could reduce its number of deployed nuclear warheads by one-third after they completed a comprehensive study of US nuclear requirements. This study had presumably reviewed both the numbers of targets that the United States needed to hold at risk and the numbers of warheads it needed to hold those targets at risk to maintain a robust deterrent. It is possible that changing views about the challenges from Russia and China might alter those calculations.

Moreover, deterrence is as much a political as a military calculation, and, when faced with growing concerns about the challenges from Russia and China, the US national security establishment might now oppose further reductions in nuclear weapons even if guidance on the required number of warheads has not changed. Some have argued that the United States might need to increase the number of deployed nuclear weapons so that it could hold at risk a growing number of Russian and Chinese targets (Bender 2021). Others have argued that, at the very least, the United States should not reduce its nuclear weapons further unless China joins arms control talks that limit its nuclear weapons.

The National Security Imperative

The bilateral nuclear arms control process will only serve as a catalyst for a step-by-step process to reduce and eventually eliminate nuclear weapons if and when the United States, Russia, and other nuclear weapons states agree that the elimination of nuclear weapons will serve their national security interests. This national security imperative guided US-Soviet arms control negotiations during the Cold War and continues to advise US-Russian arms control today. While the numbers of nuclear weapons – both deployed and in their active stockpiles – have declined significantly since the end of the Cold War, this is, in many ways, a reaction to changes in the international security environment that occurred while the two nations were negotiating their treaties.

Arms control negotiations can contribute to the participants’ security in a number of ways that are not related to reductions in the numbers of deployed nuclear weapons. The US-Soviet experience demonstrated that negotiations provided the participants with a channel to communicate about their national security concerns in tense times even when they were unable to conclude agreements. When they did sign treaties, the limits in the agreements, along with the monitoring and verification provisions, provided transparency into the capabilities of their existing forces and predictability about their plans for the future. These benefits helped manage uncertainties and dampen pressures to expand forces and capabilities in ways that could increase the costs and risks of nuclear war.

The treaty provisions also encouraged restraint in weapons programs and bolstered stability. Often the limits encouraged the parties to structure their nuclear forces in ways that would reduce incentives for a first strike in a conflict and preserve their ability to retaliate with an assured second strike if they were attacked. This strategic stability construct was evident in a statement signed by Presidents George H.W. Bush and Mikhail Gorbachev in 1990, when they pledged to pursue an agreement that would “place emphasis on removing incentives for a nuclear first strike, on reducing the concentration of warheads on strategic delivery vehicles, and on giving priority to highly survivable systems”.⁴

The US-Soviet arms control process demonstrated a preference for limiting specific types of weapons rather than explicitly reducing the numbers of deployed warheads. Both sides conducted their own assessments of the weapons they determined to be essential to their nuclear force, and each sought limits on those that they feared most on the other side. For example, the United States long sought limits on Soviet “heavy” ICBMs, the types that could carry large numbers of warheads and threaten US land-based ballistic missiles, while the Soviet Union sought limits on US submarine-launched ballistic missiles and air-launched cruise missiles, fearing that the United States might use them in a surprise attack against Soviet land-based missiles. Each, then, agreed to limits on weapons that they were willing to trade away to gain the broader security and stability benefits of arms control. Thus, even though the United States and Soviet Union sometimes signed treaties that reduced their numbers of weapons, they did so because they believed the specific reductions would bolster their own deterrent, strengthen stability and reduce the risk of nuclear war. They did not view these reductions as a symbol of their support for nuclear disarmament.

Beginning in the late 1980s, the bilateral nuclear arms control process did contribute to, or at least coincide, with a sharp decline in the numbers of US and Soviet/Russian nuclear warheads. Under the 1991 START Treaty each side was limited to 6,000 accountable warheads on land-based ballistic missiles, sea-launched ballistic missiles, and heavy bombers; the 1993 START II Treaty reduced that number to 3,500 warheads. In 2003, the United States and Russia reduced that number to 2,200 warheads in the Strategic Offensive Reductions Treaty, and New START set the limit at 1,550 warheads.

But arms control, alone, did not create this pattern. For example, the Soviet Union ceased to exist less than six months after the two sides concluded START. The United States canceled numerous programs that it had been developing to address a threat that no longer existed. Russia consolidated on its territory the nuclear-capable systems that had belonged to the former Soviet Union and was prepared to eliminate many thousands of weapons that had been removed from other former Soviet states. Hence, both sides concluded that they could maintain their security with fewer nuclear weapons because their security imperative had changed.

Even with the lowered numerical ceilings, however, the treaties did not fundamentally alter the two nations’ force structures. Both sides retained their combination of land-based, submarine-based, and bomber-delivered weapons. Moreover, the definitions and counting rules excluded many of the warheads that could be deployed on these delivery systems, blunting the required reductions. For example, START attributed only one warhead to heavy bombers, even though each could deliver many more weapons, allowing the United States and Russia to eliminate few bombers while complying with the treaty limits. New START also does not count some delivery systems that are undergoing maintenance, even though they will eventually rejoin the force and add to the warhead totals. The 2003 Strategic Offensive Reductions Treaty did not actually count anything; it allowed each party to simply declare, for itself, the number of operational warheads in its force. Thus, although the numbers of warheads counted by arms control treaties declined, changing rules and definitions allowed the parties to retain the bulk of their preferred forces⁵

Prospects for Arms Control as a Path to Disarmament

The bilateral nuclear arms control process can be seen as a series of legally binding treaties that limit or reduce the numbers of deployed nuclear weapons. But this treaty process may be stalled, with little hope for progress on near-term reductions in US and Russian nuclear weapons and a difficult security environment for negotiations on a more comprehensive agreement. A wider aperture – one that views arms control as a process that can foster transparency and communication, bolster norms, and help mitigate the risk of nuclear war – might reveal a different path forward, and, eventually, improve the prospects for nuclear disarmament.

Transparency and Communication

The United States and Soviet Union/Russia participated in nearly continuous arms control negotiations between 1970 and 2010. While they signed eight agreements during that time, the negotiating process itself was the venue for communication and the source of transparency. As global security challenges grow and the perceived risk of regional conflict increases, transparency and communication may, again, serve as the first step to mitigating the risk of nuclear war. The United States and Russia took a step in this direction when Presidents Biden and Putin agreed to establish an integrated strategic stability dialogue that would “seek to lay the groundwork for future arms control and risk reduction measures.

The United States has also long sought to engage in a strategic stability dialogue with China; this dialogue could address US concerns about the size, scope and implications of China’s nuclear modernization programs, along with China’s concerns about US missile defense deployments and other elements of the US military posture in the Indo-Pacific region. However, the Chinese government has yet to engage in bilateral talks that address its nuclear weapons policy or posture. Chinese officials generally argue that the United States and Russia, as the nuclear powers with by far the largest arsenals and the greatest capabilities, should take the first steps toward meaningful arms control. China has also rejected calls for it to offer more transparency into the size and structure of its nuclear forces, noting that these measures would only aid its adversaries in planning attacks against those forces (Pan 2016, 65).

China has not, however, rejected all forms of arms control, as it has participated in discussions in international arms control fora, including the Conference on Disarmament in Geneva. It is also a party to the Nuclear Nonproliferation Treaty (NPT) and participates in the P − 5 process, where the United States, Russia, China, France, and the United Kingdom discuss measures to reduce nuclear risks within the context of the NPT (Hoell 2019). These discussions have done little to calm concerns about growing nuclear arsenals or to reduce the risks of regional competition and the potential for escalation, but they do offer a template for future discussions on a broader agenda.

Norms

When the United States and Soviet Union participated in arms control negotiations during the Cold War, they demonstrated that they were willing to restrain their nuclear forces in the interest of averting destabilizing arms races and reducing the risk of nuclear war. They also generally agreed that any conflict could escalate to nuclear use and any use of nuclear weapons could escalate to a much broader and devastating nuclear war. It is not clear that all nations with nuclear weapons now recognize these risks; some seem to ascribe to the view that threats of nuclear use can help achieve political or military goals. Thus, all nuclear weapons states, beginning with the United States and Russia, could seek to devalue nuclear weapons in international security and recommit to a norm of restraint (Tannenwald 2020).

Presidents Biden and Putin seemed to take a step in this direction during their summit in June 2021, when they reaffirmed “the principle that a nuclear war cannot be won and must never be fought”. Presidents Ronald Reagan and Mikhail Gorbachev had first issued this statement in 1985, when they indicated that they were “conscious of the special responsibility of the USSR and the US for maintaining peace”. In recent years, some have suggested that a US-Russian reaffirmation of this statement might help bolster international nonproliferation efforts by reducing, what one expert has called, the” oversized importance” placed on “the symbolic, geopolitical, as well as military utility of nuclear weapons” (Krepon 2021b). Further, this statement, if adopted by all nuclear weapons states, might offset the impression that the nuclear weapons states seem to view these weapons as a viable tool to address regional security challenges.

A number of other normative statements might also demonstrate a reduced reliance on nuclear weapons and encourage restraint among nuclear-armed nations. These include negative security assurances, like those issued by the P-5 states in support of their obligations under the NPT, where they pledge that they will not use nuclear weapons against non-nuclear states that are in compliance with their nonproliferation obligations, and, more generally, statements where they pledge that they will not use nuclear weapons first under any circumstances⁶ Nations could also pledge that they would not resume explosive nuclear weapons tests and pledge that they would not use nuclear weapons under any circumstances, unless faced with a threat to their very existence (Krepon 2021a: Perkovich and Vaddi 2021, 34–40). While most nuclear weapons states would resist adopting these policies and bolstering these norms, discussions about the risks created by doctrines that allow for the early use of nuclear weapons and the potential benefits of norms that communicate nuclear restraint could clear a path to eventual changes that support reductions in reliance on nuclear weapons.

Nuclear Risk Reduction

During the Cold War, most analysts expected that a nuclear war between the United States and Soviet would be the result of escalation from a conventional conflict. Thus the two countries adopted a number of measures to reduce the risk that misunderstandings or miscalculations could lead to conflict and, potentially, nuclear escalation. Among other steps, they established communications links that allowed consultation during crises, pledged to provide notifications of activities like missile launches and military exercises that might lead to misunderstandings, and agreed to avoid threatening or ambiguous actions by their military forces that might raise concerns of an impending attack.

Many of the mechanisms adopted during the Cold War are eroding as a result of hybrid operations, the development of advanced military technologies, and hazardous military activities in disputed areas in both Europe and Asia. In addition, the number of countries engaging in provocative activities, including the number armed with nuclear weapons, has increased. Most experts agree that the risk of regional conflict – in Europe, Asia, and South Asia – is growing and, as a result, the risk of miscalculation, escalation, and nuclear use is also increasing. Therefore, many have proposed that the countries at risk and the international community at large consider bolstering previous risk reduction mechanisms and possibly adopting new ones⁷ These mechanisms could include establishing lines of communication, holding consultations on doctrine and operations to reduce the risk of misunderstanding in a crisis, providing detailed notifications about potentially ambiguous exercises and operations, and cooperating in reducing regional tensions so that crises do not emerge and never have a chance to escalate.

Few of these measures would impede military operations if a conflict did occur, but they could open channels for communication in peacetime that could prove useful during a crisis. Moreover, as was the case with the United States and Soviet Union during the Cold War, cooperation in one area can foster cooperation in other areas, thus possibly reducing tensions and permitting a broader change in the security environment. This, in the long run, might help some countries reduce their reliance on nuclear weapons.

Conclusion

An arms control agenda that focuses on transparency, communication, norms, and risk reduction may seem inadequate to the task of paving a path to nuclear disarmament because it acknowledges that some nations may continue to possess and rely on nuclear weapons. For those who see nuclear weapons as the primary source of global insecurity and a threat to human survival, an agenda that does not begin with a pledge to eliminate those weapons is insufficient. However, the nations that now possess nuclear weapons see these weapons as essential to their security. They will not eliminate them until the security environment changes. Moreover, it may be difficult, in the next few years, for the United States, Russia or any other nuclear weapons state to cooperate in reducing their nuclear arsenals. Under these circumstances, an agenda that focuses on risk reduction, rather than weapons reductions, may not only serve as a temporary venue for negotiations, but may also create opportunities for the parties to address and resolve those security concerns that are blocking the path to nuclear disarmament.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Amy F. Woolf

Amy F. Woolf is a Specialist in Nuclear Arms Control at the US Congressional Research Service. The views here are her own and are not necessarily shared by the Congressional Research Service or the Library of Congress.

Notes

¹ See, for example, Perkovich and Acton (2009)..

² “Strategic stability must be the focus of Russia-US negotiations, says Lavrov,” Tass, 17 May 2021.

³ See, for example, the discussion in Egel and Vaynman (2021)..

⁴ George H.W. Bush Presidential Library and Museum. Soviet-United States Joint Statement on Future Negotiations on Nuclear and Space Arms and Further Enhancing Strategic Stability, 1 June 1990. https://bush41library.tamu.edu/archives/public-papers/1938.

⁵ The United States has retained essentially the same force structure under New START in 2021, with its limit of 1,550 warheads, as it had planned to retain under START II, with its limit of 3,500 warheads, in 2000..

⁶ At present, China is the only nuclear weapons state to adopt an unconditional “No first use” pledge, and many analysts have questioned whether it would hold to that pledge in all circumstances..

⁷ For detailed discussions of this issue see Wan (2020)..