Senate Shapes Nuclear Arsenal Policy Behind Closed Doors

Why it Matters

The Senate Armed Services Committee's Subcommittee on Strategic Forces convenes June 9 for its closed NDAA 2027 hearing — a markup session that will quietly shape the most consequential decisions in American defense policy: how many nuclear warheads to field, whether to accelerate or constrain the troubled Sentinel ICBM program, and how the United States positions its strategic forces in a post-New START world where treaty constraints on Russian and American arsenals have lapsed. What happens behind closed doors in 232A Russell will determine billions in nuclear modernization spending and set the trajectory of U.S. deterrence policy for years.

The Strategic Stakes

The House Armed Services Committee set the table when it released its version of the defense authorization bill on May 27, proposing nearly $1.15 trillion in total defense funding — including roughly $42 billion for nuclear weapons programs at the National Nuclear Security Administration. That figure lands squarely in the Strategic Forces Subcommittee's lane, and the Senate's version will either match, exceed, or trim it.

The subcommittee's jurisdiction is narrow but consequential: nuclear weapons programs, missile defense, space forces, and strategic command policy. The senators in that room — chaired by Deb Fischer of Nebraska, with Maine independent Angus King as ranking member — will be deciding the funding and policy parameters for the Sentinel ICBM, the Columbia-class ballistic missile submarine, and the B-21 Raider bomber. All three programs are in active development. None is cheap. All are behind schedule.

The Sentinel Problem

No issue looms larger over this NDAA 2027 hearing than the Sentinel ICBM, the Air Force's planned replacement for the aging Minuteman III. The program triggered a Nunn-McCurdy cost breach — a statutory threshold requiring formal recertification when a major defense program's costs spiral beyond set limits — and U.S. Strategic Command's 2026 congressional posture statement noted that a Milestone B recertification was "scheduled for not later than 2026." That milestone is a formal cost, schedule, and performance review. Its outcome will shape what the subcommittee can responsibly authorize.

Fischer has been among the Senate's most aggressive advocates for nuclear modernization and has used prior NDAA markups to codify requirements — including a mandate that no fewer than 400 ICBMs remain on alert, a provision written into Title 10 of U.S. Code in the FY2026 cycle. The FY2027 markup is where she and her colleagues decide whether to hold the line on that requirement, accelerate Sentinel's fielding timeline, or respond to the Milestone B recertification with new oversight conditions.

A Post-New START World

The broader policy environment makes this Senate SASC hearing more consequential than a typical annual markup. The New START treaty — the last remaining bilateral arms control agreement between the United States and Russia — has expired, and with it the verification mechanisms and warhead limits that structured American nuclear planning for over a decade. A 2026 Atlantic Council analysis argued the U.S. must now expand its nuclear forces, citing the 2026 National Defense Strategy's stated intent to "adapt U.S. nuclear forces." The Trump administration has not yet directly addressed nuclear force size, but the NDS language signals the question is live.

A 2026 Department of State report cited in congressional research noted no large-scale increase in Russian warhead levels had yet been detected — but acknowledged continued monitoring. That assessment matters to the subcommittee because it is the intelligence baseline against which U.S. force sizing decisions are made.

The Congressional Research Service confirmed in April 2026 that the Defense Department "is in the process of modernizing U.S. strategic nuclear forces" — a statement that understates the complexity. Modernizing all three legs of the nuclear triad simultaneously, without a binding arms control framework, while managing Sentinel's cost overruns, is the challenge Fischer's subcommittee must navigate in this markup.

The Senate-House Parallel Track

The NDAA 2027 hearing on the Senate side runs parallel to House action. The House Armed Services Committee introduced H.R. 8800 on May 13, 2026, with Chairman Mike Rogers and Ranking Member Adam Smith as co-sponsors, and scheduled its own markup for June 4. The Senate subcommittee's closed session on June 9 is the first step in the Senate's own drafting process, with the full SASC committee markup scheduled for June 10.

The bicameral process means the two chambers will produce separate versions that must eventually be reconciled in conference. Historically, the Senate's Strategic Forces subcommittee mark has differed from the House version on nuclear policy specifics — particularly on questions of missile defense architecture, space force authorities, and NNSA funding levels. Those differences will be negotiated later. For now, the subcommittee's closed markup is where the Senate's opening position gets set.

Who's in the Room

Fischer chairs a subcommittee that includes some of the Senate's most hawkish voices on defense. Tom Cotton of Arkansas and Kevin Cramer of North Dakota — whose state hosts Minot Air Force Base, home to both bomber and ICBM forces — have been consistent advocates for accelerating nuclear modernization. Mike Rounds of South Dakota, another ICBM-state senator, brings similar pressure. On the Democratic side, King, Mark Kelly of Arizona, and Jack Reed of Rhode Island bring oversight instincts and, in Kelly's case, a former astronaut's familiarity with space-based strategic systems.

Elizabeth Warren's presence is notable — she has historically pushed back on open-ended nuclear modernization costs and has used NDAA markups to attach oversight requirements to troubled programs. Whether she presses on Sentinel's Nunn-McCurdy recertification in this session is one of the few unknowns in an otherwise predictable partisan alignment.

Because the session is closed, the specific provisions under consideration will not be publicly disclosed until the full committee releases its mark following the June 10 vote.