Why It Matters

For the first time since the 1970s, the United States and Russia are operating without formal numerical constraints on their strategic nuclear forces. The expiration of the New START Treaty on Feb. 5 removed the last major bilateral arms control agreement governing deployed strategic warheads and delivery systems, leaving the world's two largest nuclear arsenals without legally binding numerical limits or treaty-based verification measures. As Congress confronts this reality, lawmakers are finding their influence over nuclear weapons reduction and strategic arms limitation remains structurally constrained, even as geopolitical tensions mount.

Congress wants action on nuclear risk reduction policy, but the executive branch controls the diplomatic levers. The Trump administration has prioritized nuclear modernization over arms control, while Russia has sought policy concessions before pursuing a successor agreement and China has continued to decline participation in trilateral negotiations. Meanwhile, Congress is attempting to exercise oversight and encourage action through the National Defense Authorization Act process and standalone legislation, even as experts warn that the absence of formal agreements increases the risk of miscalculation.

The Big Picture

The New START Treaty, signed in 2010, was the last major framework limiting strategic nuclear weapons between Washington and Moscow. Its expiration left both nations without binding caps on deployed warheads, strategic bombers and intercontinental ballistic missiles. Russian officials have conditioned broader negotiations on changes in overall U.S. policy toward Russia and criticized what they described as the Trump administration's lack of interest in Russia's September 2025 proposal to continue observing New START's numerical limits for one year after expiration. President Donald Trump rejected a Russian offer for a voluntary one-year extension of those deployment caps. Informal discussions regarding selected risk-reduction measures have continued, but no successor treaty has replaced New START.

The Senate Armed Services Committee characterized the post-New START environment as "Strategic Competition in an Unconstrained, post-New START Treaty Environment," reflecting the strategic uncertainty now defining U.S.-Russia nuclear relations. Without New START caps, the U.S. is no longer beholden to limitations on the size of its SSBN fleet, opening new pathways for nuclear force expansion.

The legislative branch has attempted to exercise oversight and encourage action through the NDAA process and standalone legislation addressing nuclear risk reduction. The House Armed Services Committee-reported National Defense Authorization Act for Fiscal Year 2027, H.R. 8800, includes a provision requiring the Defense Department to report on activities supporting arms control and nuclear risk reduction objectives, including recommendations for key attributes of a future multilateral arms control agreement. The Senate Armed Services Committee-reported FY2027 NDAA, S. 4784, includes a provision directing Defense Department officials to brief congressional defense committees on existing and potential nuclear and space risk reduction measures involving the United States, Russia and China.

H.Res. 100 calls for U.S. dialogue with Russia and China on nuclear risk reduction and arms control and calls for Russia to return to full New START implementation. Its Senate companion, S.Res. 61, urges the administration to pursue nuclear arms control and risk reduction with Russia and China. H.Res. 317 calls for good-faith negotiations with nuclear-armed states, including pursuing new U.S.-Russia arrangements and engaging China on mutual nuclear risk reduction. Its Senate companion, S.Res. 323, urges the United States to lead a global effort to halt and reverse the nuclear arms race. Sen. Edward Markey authored S. 3356, the HALT Act of 2025, which calls for head-of-state summits on nuclear disarmament and urges Senate ratification of the Comprehensive Nuclear-Test-Ban Treaty.

S. 192, the Restricting First Use of Nuclear Weapons Act of 2025, prohibits the use of federal funds for a first-use nuclear strike unless Congress expressly authorizes it through a declaration of war. H.R. 669 is the House companion measure. H.R. 3564, the Nuclear First-Strike Security Act of 2025, addresses presidential authority over nuclear first strikes.

H.R. 8086 would codify the State Department's National and Nuclear Risk Reduction Center, reporting to the under secretary of state for arms control and international security. The NNRRC was first proposed in 1982 and established by the Reagan administration in 1987, representing a decades-old institutional framework for managing nuclear risk that Congress now seeks to formalize.

Political Stakes

For the Trump administration, the calculus is straightforward: nuclear modernization takes precedence over traditional bilateral arms control. An under secretary of state said in February that the United States would pursue responsible pathways to reduce the number of nuclear weapons consistent with the administration's vision and obligations under the Nuclear Non-Proliferation Treaty. In July, the secretary of state said that "if you're going to have true arms control, it has to be triparty," involving the United States, Russia and China. That framing raises the bar for any near-term agreement because China has repeatedly declined to join trilateral nuclear negotiations, arguing it maintains a much smaller nuclear arsenal than either the United States or Russia.

Congress faces structural limitations in influencing nuclear arms control because treaty negotiations remain primarily an executive branch responsibility. At the same time, the 2023 Congressional Commission on the Strategic Posture of the United States concluded that arms control and risk reduction measures can reduce uncertainty and the risk of miscalculation.

China provided little advance notice to the United States before its July 6 submarine-launched ballistic missile test, underscoring the transparency gaps widening in the post-New START environment. North Korea has rejected negotiations since talks collapsed in 2019. India-Pakistan tensions also remain a potential source of nuclear escalation, according to the 2026 Annual Threat Assessment of the U.S. Intelligence Community, although the United States helped facilitate some bilateral risk-reduction efforts in spring 2025.

The Bottom Line

Congress is attempting to advance nuclear risk reduction policy through multiple legislative vehicles while acknowledging the executive branch's constitutional role in negotiating arms control agreements. The Congressional Research Service report, published July 24, documents both the breadth of congressional activity and the institutional constraints limiting lawmakers' influence.

Congress has called for renewed dialogue with Russia and China on nuclear risk reduction and arms control. The Trump administration, by contrast, has emphasized pursuing nuclear risk reduction through the permanent five, or P5, process involving the United States, Russia, China, the United Kingdom and France.

According to a May State Department statement, U.S. proposals for new P5 working groups and ballistic missile launch notification measures had not reached consensus. Responsibility for negotiating future arms control agreements ultimately remains with the executive branch, which has thus far prioritized modernization while expressing interest in negotiating a broader successor agreement rather than extending New START.

Access the Legis1 platform for comprehensive political news, data, and insights.

Spot something wrong? Report an issue with this article