Updated January 2023
The Biden administration has decided against developing a new nuclear-armed sea-launched cruise missile (SLCM-N) and its associated warhead. In FY23 budget documents, the Navy stated that “the program was cost prohibitive and the acquisition schedule would have delivered capability late to need.” Despite the Navy’s opposition and concerns the SLCM would negatively affect readiness, both the FY23 defense authorization and appropriations bills included $45 million in funding for the SLCM-N and its associated warhead, the W80-4 ALT.
In 1991, President George H.W. Bush ordered all nuclear-armed Tomahawk Land Attack Missiles removed from U.S. submarines and placed in storage. In 2010, the Obama administration declared the missiles a redundant capability and retired them. The Trump administration’s 2018 Nuclear Posture Review called for the development of a new SLCM-N to fill a theoretical gap in the U.S. arsenal for a low-yield nuclear response despite repeated DoD assurances that U.S. deterrence remained effective without SLCM. The Congressional Budget Office estimates a new SLCM-N will cost at least $10 billion through 2031. That total does not include production costs after 2031, retrofitting submarines and surface ships to carry the weapon, or other operational or security costs, which officials have hinted could lead to a total cost of up to $30 billion.
Senior Department of Defense officials shared varying opinions on the SLCM-N with Congress in the FY23 budget cycle. In April 2022, Chairman of the Joint Chiefs of Staff Gen. Mark Milley testified that he continues to support the program. Similarly, the former head of U.S. Strategic Command, Adm. Charles Richard, and the head of U.S. European Command, Gen. Tod Wolters, both supported the program in front of Congress as well. Secretary of Defense Lloyd Austin, on the other hand, opposed the system, arguing that the SLCM-N provides marginal capability compared to its cost.
A Deterrence Gap?
The argument for the SLCM-N has been raised in the context of the war in Ukraine as well. For example, Adm. Richard used the war in Ukraine as an example of a “deterrence and assurance gap” to justify the SLCM-N in an April 2022 letter to House lawmakers. Russia does, in fact, possess nuclear-capable missiles on its naval vessels; however, the SLCM-N would not be delivered before the 2030s and is therefore not relevant to the current war in Ukraine. There is also no indication that the addition of the SLCM-N would deter any future action by an adversary, such as Russia or China, and no SLCM-N type capability has been used in Ukraine or elsewhere.
Unwanted, Costly and Redundant
A new SLCM-N is a costly solution to a nonexistent problem. It is not necessary for deterrence, and pursuing such a program would be an expensive exercise that would do little to enhance U.S. security.
- SLCM-Ns weaken the U.S. Navy’s conventional warfighting duties. Arming U.S. surface or attack submarine fleets with SLCM-Ns means less space for conventional weaponry, weakening U.S. conventional capabilities and potentially leaving even fewer ships available for the Navy’s already overstretched mission set. It would also either bring nuclear weapons back to states that don’t currently house them, or force Navy ships to go out of their way to pick them up before deployment. Some U.S. allies like Japan and New Zealand also prohibit nuclear-armed vessels from docking at their ports or engaging in joint training exercises, presenting additional diplomatic challenges and resupply issues.
- The United States already has plenty of lower-yield nuclear options. The B61 gravity bomb, the W80-equipped air-launched cruise missile, and the W76-2 sea-launched ballistic missile are all low-yield capabilities already existing in the arsenal. The United States can meet adversaries at any escalation level with its current conventional and nuclear means. Adding a new SLCM-N would be a costly hedge built on an existing hedge.