GBSD

The Ground Based Strategic Deterrent (GBSD) is the United States Air Force program to develop and field a new land-based intercontinental ballistic missile (ICBM) to replace the aging LGM-30G Minuteman III, which has been in service since the 1970s. In September 2020, Northrop Grumman was awarded the engineering and manufacturing development contract for GBSD after Boeing declined to submit a competing bid. In April 2022, the Air Force formally redesignated the missile the LGM-35A Sentinel, though "GBSD" remains widely used in policy and arms-control literature.

GBSD/Sentinel is intended to constitute the land leg of the US nuclear triad through roughly 2075, alongside the Columbia-class ballistic missile submarine and the B-21 Raider bomber. The program covers not only the missiles themselves but also new command-and-control systems and extensive refurbishment of launch facilities and silos across F.E. Warren, Malmstrom, and Minot Air Force Bases in Wyoming, Montana, North Dakota, Colorado, and Nebraska.

The program has drawn significant attention for cost growth. In January 2024, the Pentagon disclosed that Sentinel had breached the Nunn-McCurdy Act threshold, with projected unit costs rising roughly 37% above baseline. Following a mandated review, the Department of Defense in July 2024 certified the program to continue but ordered a restructuring.

Critics, including some arms-control analysts and members of Congress, have argued that silo-based ICBMs are destabilizing because they invite counterforce targeting and force "launch-on-warning" postures. Proponents counter that the dispersed silo field complicates adversary planning and provides a responsive, survivable deterrent leg. The debate intersects with broader questions about US nuclear modernization costs, extended deterrence commitments to NATO and Indo-Pacific allies, and the future of strategic arms control after the expiration of New START in February 2026.