Why US strategic nuclear forces must expand after New START
AI Analysis
The expiration of the New START treaty has sparked a debate on the expansion of US strategic nuclear forces. The US may need to increase its nuclear arsenal to 2,400 operationally deployed warheads to maintain strategic deterrence, while balancing flexibility and force attributes.
Key Takeaways
- The New START treaty has expired, prompting a reevaluation of US nuclear posture.
- The US may need to expand its nuclear arsenal to 2,400 warheads.
- Flexibility and force attributes are as important as the number of warheads.
- The National Defense Strategy lacks details on nuclear policy post-New START.
- There is concern over a potential arms race with China and Russia.
Why It Matters
The expiration of the New START treaty and potential expansion of US nuclear forces could significantly impact global strategic stability. It raises concerns about a new arms race, particularly with major powers like China and Russia, and the need for careful policy decisions to manage escalation risks.
Why US strategic nuclear forces must expand after New START - Atlantic Council
Bottom lines up front
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- The United States needs a nuclear force larger than today’s and flexible enough to influence adversary decision-making at all stages of crisis and conflict.
- A US strategic deterrent capable of delivering roughly 2,400 operationally deployed warheads in the near term should be sufficient to meet US strategy requirements.
- Force attributes and flexibility matter as much as numbers, though.
Now that the New Strategic Arms Reduction Treaty has expired, the debate begins over what the United States should do next regarding its nuclear posture. The recently released National Defense Strategy (NDS) sheds little light on the Trump administration’s plans; it does not even mention New START. Instead, the NDS largely eschews details on US nuclear policy and capabilities, noting only that the United States “will modernize and adapt our nuclear forces accordingly with focused attention on deterrence and escalation management.” 1 U.S. Department of Defense, 2026 National Defense Strategy of the United States of America (Washington, DC: Department of Defense, January 23, 2026), https://media.defense.gov/2026/Jan/23/2003864773/-1/-1/0/2026-NATIONAL-DEFENSE-STRATEGY.PDF. What this means for US force size and posture will play out over the coming months and years, likely beginning with submission of the president’s annual budget request later this spring.
In anticipation of this debate, many commentators urge caution, suggesting that any expansion in US force size (even in response to actions by China and Russia) could prompt an uncontrolled arms race. 2 Mark Trevelyan, “Explainer: What Is the New START Nuclear Treaty and Why Does Its Expiry Matter?” Reuters, January 30, 2026, https://www.reuters.com/world/what-is-new-start-nuclear-treaty-why-does-its-expiry-matter-2026-01-30/. Others argue that the United States has time to prepare for the emerging threats it faces so there is no need to panic, suggesting that adjustments can wait until the country gets closer to the end of the existing modernization program of record. 3 Rose Gottemoeller, “Testimony before the Senate Foreign Relations Committee on an ‘Arms Race 2.0,’”US Senate, December 10, 2025, https://www.foreign.senate.gov/imo/media/doc/f44409cc-cc99-f286-066b-1283777d682b/121025_Gottemoeller_Testimony.pdf. Still others contend that the United States already has enough nuclear weapons and that force growth would be expensive and counterproductive. 4“Expiration of US-Russia Agreement Could Trigger Rapid, Dangerous Nuclear Arms Race, New Report Warns,”Union of Concerned Scientists, January 12, 2026, https://www.ucs.org/about/news/nuclear-agreement-expiration-could-trigger-rapid-arms-race.One specific argument points to a 2013 Obama administration assessment that the US nuclear force