We Don’t Have Enough Information to Evaluate Arguments for a New ICBM

The politics of American nuclear modernization are heating up. As defense budgets come under increased scrutiny, lawmakers are taking a close look at the future of the ground-based leg of America’s nuclear triad. On the current course, the country’s 400 single-warhead, silo-based LGM-30G Minuteman III intercontinental ballistic missiles are slated for modernization and replacement with a new nuclear missile known as the Ground-based Strategic Deterrent.

GBSD’s strategic value-add over Minuteman III is nil to negligible. Like the Minuteman III, which first deployed in 1970 and has seen rounds of life-extensions into the mid-2010s, the GBSD will serve largely as a “warhead sponge.” As long as 400 American ICBMs remain ready to launch in their silos, Russian planners must assign their own warheads to these targets. Given their primary function as a tripwire, the qualitative nature of those missiles is a secondary matter. 

Yet this qualitative case for GBSD has received considerable airtime from its proponents. U.S. Strategic Command’s case for the GBSD—as made by STRATCOM commander Adm. Charles Richard last month—is straightforward: though the Minuteman III is “fully reliable today,” GBSD brings new capabilities to the table. These include improvements to the system’s security during warhead maintenance, lower manpower requirements for sustainment, and great modularity. More practically, GBSD is expected to make use of composite materials in its airframe—like the intercontinental Trident D5 submarine-launched ballistic missile, the cornerstone of the U.S. sea-based deterrent—and thereby may offer a throw weight increase over Minuteman III.

Adm. Richard also has argued that it would not be “cost-effective” to life-extend Minuteman III further, in part because certain decades-old parts are no longer attainable. 

Secrecy and classification make public debate of these aspects of ICBM modernization challenging. STRATCOM’s arguments concerning the safety, security, and modularity benefits of GBSD over the existing Minuteman III are not easily refuted through open-source evidence alone. 

To facilitate informed public debate and astute decision-making concerning the future of the American ICBM force, Congress should commission an independent review and assessment of the feasibility of and risks associated with a further life-extension of the Minuteman III. Such a review could explore alternative possibilities, including silo-basing the Trident D5—the intercontinental-range submarine-launched ballistic missile used by the U.S. Navy. 

Similar studies were carried out before the conclusion of the latest round of life-extensions of the Minuteman III. For instance, a 2014 RAND Corporation analysis found that “incremental modernization and sustainment of the current Minuteman III force is a cost-effective alternative” over an entirely new ICBM. A similar conclusion was reached in 2017 by the Congressional Budget Office, which examined the possibility of a further Minuteman III life-extension alongside planned upgrades to command-and-control and launch-control-center infrastructure. A new study could help evaluate, for instance, Adm. Richard’s April claim that Minuteman III’s command-and-control limitations make the case for GBSD. 

The National Academies of Sciences, Engineering, and Medicine would be ideally suited to field a new mandate for a study, convene an independent expert group, and conduct a study. The study could provide both an unclassified and classified assessment, with the latter designed to delve into the otherwise difficult-to-falsify arguments that have been made in support of GBSD by Strategic Command and others.

Should Congress fail to act, the Biden administration should consider tasking the Defense Department to sponsor work by the JASON scientific advisory group to undertake a similar study. According to recent reporting, DoD’s Cost Assessment and Program Evaluation office may already be conducting similar analysis. The outcome of such a study could further support the administration’s likely upcoming Nuclear Posture Review or other integrated strategic deterrence review.

Unfortunately, these studies will need to happen soon. With the engineering and manufacturing contract for GBSD now having been awarded to Northrop Grumman and the completion of an Integrated Baseline Review, the next-generation ICBM is on its way to its planned initial operating capability date sometime in fiscal year 2029. Charting an alternative course on America’s near-term ICBM force could also support mutual arms reductions with Russia.

No path will be entirely risk-free when it comes to the future of the U.S. ICBM force, but Americans deserve a serious assessment of the costs, benefits, and risks associated with each possible path ahead. With GBSD’s massive financial costs looming on the horizon, lawmakers and the administration should be unafraid of absorbing sunk costs and changing course in the coming months and years should independent technical, fiscal, and risk assessments favor further life-extending Minuteman III.