Why it Matters
The Senate Foreign Relations Committee convened a March 24, 2026 hearing at the Dirksen Senate Office Building on arms control and the State Department's restructured international security functions — arriving weeks after the last major U.S.-Russia nuclear treaty expired with no successor in place. The Trump administration's position is clear: the old bilateral arms control framework is obsolete, and any new deal must include China. That posture collided directly with Democratic warnings that the administration is dismantling the very bureaucratic infrastructure needed to negotiate what comes next.
The Big Picture
The hearing landed at a moment of cascading strategic disruption. New START — the last binding limit on U.S. and Russian nuclear arsenals — expired February 5, 2026, after President Trump declined to extend it, calling it "a badly negotiated deal." Simultaneously, Secretary of State Marco Rubio's sweeping State Department reorganization is merging the arms control and nonproliferation bureaus into a single office, cutting roughly 22 percent of the "T Family" staff. The Arms Control Association has warned the consolidation "likely will reduce the capacity of the department and the government as a whole" on these issues. Chair Sen. Jim Risch (R-ID) has previously stated flatly: "The Cold War nuclear arms control paradigm is dead."
The sole witness was Thomas DiNanno, Under Secretary of State for Arms Control and International Security, appearing in his first full oversight hearing since confirmation.
What They're Saying: Senate Hearing Roundup Highlights
Sen. Jim Risch (R-ID): "Russia is a serial treaty violator — that's putting it kindly."
Sen. Jeanne Shaheen (D-NH): "Waiting for perfect conditions while things are moving in the wrong direction is not a plan."
Sen. Jeff Merkley (D-OR): "If Saudi Arabia gets a deal without covering enrichment or reprocessing — count me concerned."
Shaheen fired back early, warning that U.S. Gulf partners are "burning through interceptors at a staggering rate, using in a day what the United States produces in a year." She pressed DiNanno directly on how the U.S. maintains credibility without any binding limits or inspection regime on Russian forces.
DiNanno was at times combative. When a senator raised the possibility of resumed nuclear testing, he broke in mid-exchange: "Hold on — I want to address that. There is no discussion that I've been a part of where any atmospheric testing would take place." On the pending Saudi Arabia civilian nuclear cooperation agreement, he repeatedly declined to confirm whether it would meet the so-called "gold standard" of prohibiting enrichment and reprocessing, saying only that it would meet "minimum standards" under the Atomic Energy Act — a distinction that visibly frustrated Merkley and Sen. Chris Van Hollen (D-MD).
Van Hollen landed one of the hearing's sharpest moments, stating that President Trump's claim Iran would have had a nuclear weapon within two weeks of U.S. military action was "manifestly untrue based on all the testimony we've seen from the intelligence community."
Even Sen. John Cornyn (R-TX) pressed DiNanno on an apparent contradiction: a State Department statement supporting the U.K.-Mauritius Chagos Archipelago deal ran directly counter to the president's own public position. DiNanno did not resolve the discrepancy.
Political Stakes
DiNanno is navigating two simultaneous vulnerabilities: defending the substance of a post-New START world with no successor framework, while also defending an organizational restructuring that critics say hollows out the very expertise needed to negotiate one. His admission that he personally reviewed and signed hundreds of arms sales — including an emergency $16 billion transfer to Middle East partners — gave Democrats a concrete accountability hook.
For the administration, the stakes are institutional. The reorganization is fully implemented by July 1, 2025, leaving Congress a narrow window to conduct oversight before structural changes lock in. A March 2025 House Foreign Affairs subcommittee hearing revealed that most arms control bureaus carry no statutory authorization — meaning the executive can reorganize or eliminate them without congressional approval.
The Other Side
Not all analysts view the restructuring as purely destructive. The Carnegie Endowment for International Peace has argued the reforms are "an opportunity to strengthen the bureaucratic, diplomatic, and strategic effectiveness" of the State Department's arms control mission. DiNanno's call for a multilateral framework covering China and Russia's tactical weapons — categories New START never addressed — has some analytical support, even among critics of the administration's overall approach.
What's Next
A Senate Foreign Relations Committee hearing on State Department reform is scheduled for July 16, 2026, which will serve as a direct follow-up as the reorganization's effects become visible. DiNanno flagged imminent P5 multilateral engagement where Russia's exotic nuclear systems — including a nuclear-powered cruise missile that falls outside New START's scope — will be raised. On AUKUS, DiNanno explicitly asked the committee for "regulatory and legislative relief" to untangle Cold War-era export control frameworks constraining allied technology sharing.
The Bottom Line
With no nuclear treaty in force, a State Department being restructured mid-negotiation, and Iran's enrichment capacity now measured in weeks rather than years, the Senate hearing statements from this session will serve as the opening record of what may be the most consequential arms control debate in a generation.
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