From Bilateralism to Multilateralism: Washington’s Push for Strategic Stability Through the P5

Published: May 5, 2026

With the New START’s expiration on February 5, 2026, the world has entered a new era in nuclear arms control, reflecting the evolving realities of the contemporary nuclear order. The United States believes that nuclear limits on warheads and launchers imposed under the New START no longer serve its interests, or those of its nuclear adversaries, highlighting Washington’s lack of appetite for a renewed bilateral arrangement. Dr. Christopher Yeaw, the U.S. Assistant Secretary of State for the Bureau of Arms Control and Non-Proliferation, shared the U.S. perspective at the Conference on Disarmament (CD), shifting from exclusive U.S.-Russia strategic constraints toward a more inclusive yet complex multilateral framework that could shape the future of global nuclear stability. This transition shows a broader shift in arms control policy of the U.S., emphasizing the need for a new arms control arrangement that reflects a transition from a bilateral framework to a multilateral charter, holding all five nuclear-weapon states under the Treaty on the Non-Proliferation of Nuclear Weapons (P-5) equally responsible for making serious efforts toward nuclear disarmament.

While addressing the CD, Dr. Yeaw used the shortcomings of the New START to advance a broader strategic argument rather than merely listing Russian violations. By emphasizing Russia’s sizeable stockpile of non-strategic (theatre) nuclear weapons that are estimated to be around 2,000 warheads and the production of novel systems like nuclear-armed Skyfall cruise missile and the nuclear powered Poseidon torpedo, Washington aimed to highlight that New START was overly focused on deployed strategic warheads and completely overlooked the full range of modern nuclear risks.

Dr. Yeaw further linked these loopholes with China’s emergence as a major nuclear actor, arguing that the New START bilateral structure left a structural gap by excluding Beijing at a time of unprecedented expansion in its nuclear arsenal. While projecting on China’s official defense white papers, he cautioned that Beijing could attain strategic parity in the next four to five years and may possess fissile material sufficient for more than 1,000 warheads by 2030, which was roughly 200 at the time the treaty was signed in 2010. Additionally, he highlighted concerns about Russian cooperation on China’s CFR-600 reactors, framing this collaboration as further complicating U.S. threat perceptions. Through these arguments, Washington justifies a shift from a bilateral arms control framework with Russia toward a multilateral platform that includes additional nuclear stakeholders, reflecting a recalibration of the U.S. arms control policy in the contemporary multipolar nuclear landscape.

The U.S. believes that New START’s expiration arrived at the fortuitous time, urging all states, not just the nuclear-weapon states, to strive for a better arms control framework. Under the new proposal, Washington aims to transition from a bilateral arms control agreement with Russia to a multilateral platform as a necessary next step in ongoing arms control discussions. Such a multilateral format can prevent an unmitigated nuclear arms race, restrain the build-up of nuclear arms, and address issues surrounding non-NPT states with nuclear weapons. In a multilateral format, the Trump administration says all options are on the table as it discusses the future of nuclear arms control in the current security environment. Washington wants to conduct negotiations on strategic stability and arms control on multiple avenues, including the P5 forum where NPT-recognized nuclear-weapon states already meet to discuss issues of strategic importance. The Trump administration maintains that all five nuclear-weapon states (P5) are under an obligation to negotiate nuclear disarmament in good faith under Article 6 of the Nuclear Non-Proliferation Treaty (NPT), and that disarmament efforts are not limited to those states with the largest arsenals. Under this new proposal, the U.S. wants nuclear weapon states like Russia and China to participate in a multilateral process for effective debate on the elements of arms control arrangements.

In the evolving multipolar nuclear order, bringing together all five nuclear-weapon states to the NPT – Russia, China, France, the United Kingdom, and the U.S. admits that today’s strategic stability extends beyond Russia-U.S. dynamics. This forum could prove effective in preserving normative commitments under the Nuclear Non-Proliferation Treaty. However, asymmetries in nuclear capabilities and divergent threat perceptions limit the viability of such a multilateral forum. The U.S. and Russia still possess 80 percent of the global nuclear arsenal, while Beijing would resist numerical limits without prior reductions by the U.S. and Russia. France may support such a multilateral dialogue with other P5 states, maintaining its independent nuclear deterrent. However, Paris would likely resist any binding multilateral commitments that could limit its small arsenal. The United Kingdom may support the U.S. initiative for expanding P5 engagement.

The imperative of arms control is encouraging, but given the evolving global nuclear order, where New START failed to achieve its objectives, it is difficult to see how the proposed multilateral, modernized approach might succeed soon. In this scenario, a multilateral forum like the P5 would remain a consultative platform rather than serve as a substitute for enforcing arms control agreements.

In conclusion, after New START’s expiration, the U.S. has moved from bilateral arms control with Russia to a broader multilateral strategy, encouraging all NPT nuclear-weapon states, through forums like the P5, to share responsibility for strategic stability. This favors a more flexible approach to multilateral engagements over the binding bilateral constraints of the past in a changing security environment.

Nawal Nawaz is a researcher at the Centre for International Strategic Studies (CISS) in Islamabad. She is pursuing her MPhil in Strategic Studies at the National Defence University in Islamabad, focusing on nuclear deterrence, arms control, and regional strategic stability.