The US is developing a new submarine-launched nuclear cruise missile (SLCM-N), but its value is debated, according to War on the Rocks. Supporters say it boosts deterrence and escalation control, while critics argue it’s costly and misaligned with the current US strategy, which emphasizes conventional and strategic nuclear forces. They write:

In recent months, intensifying conflict around the world has called new attention to the possibility of military confrontation between nuclear-armed states. To meet these challenges, the United States is engaged in a substantial modernization of its own nuclear capabilities, including a new nuclear-armed cruise missile for its submarine force, commonly referred to as “SLCM-N,” or sea-launched cruise missile–nuclear. For several years, American strategists have debated the wisdom of this weapon. Critics argue that the missile poses steep opportunity costs, both in terms of the industrial resources necessary to build the weapon and in the scarce operational assets on which it would be deployed. Proponents of the missile reply that the U.S. Navy has deployed nuclear cruise missiles before, and that there is no reason it should not be able to do so again.

Both sides are ultimately correct: A nuclear sea-launched cruise missile is both possible and costly. Balancing these two perspectives ultimately requires us to go back to strategy, to understand how the United States uses its nuclear forces. […]

Given its limited contribution to current American strategy, the costs of a submarine-launched nuclear cruise missile outweigh its benefits. Proponents of a new cruise missile are correct that the United States deployed such a weapon in living memory.  […]

A submarine-launched nuclear cruise missile might make sense for a different sort of strategy. If the United States ever reverted to regular threats of nuclear escalation, as it did in the Cold War, then proliferating nuclear cruise missiles would support American strategy, even as the wisdom of such a strategy would bear close scrutiny. Developing a new nuclear cruise missile for submarines might therefore make sense as a hedge against a future change in strategy. Under current strategy, however, deploying a new nuclear cruise missile aboard submarines should not be a priority.

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