SLCM-N (Sea-Launched Cruise Missile – Nuclear) is a proposed U.S. naval nuclear weapon first formally recommended in the 2018 Nuclear Posture Review under the Trump administration. It is conceived as a non-strategic, low-yield nuclear warhead mated to a sea-launched cruise missile, deployed on attack submarines and potentially surface combatants, to provide a regionally deployable nuclear option below the threshold of strategic ballistic-missile use.
The rationale offered by its proponents has three parts:
- Closing a perceived capability gap with Russia, which fields a range of non-strategic nuclear systems.
- Reassuring allies in the Indo-Pacific and Europe without requiring forward-basing of nuclear weapons on their territory.
- Restoring a capability the U.S. retired when the TLAM-N (nuclear Tomahawk) was withdrawn from service, a decision finalized under the Obama administration's 2010 Nuclear Posture Review.
The program has been politically contested. The 2022 Nuclear Posture Review issued under the Biden administration recommended cancellation, arguing the capability was redundant given other low-yield options such as the W76-2 warhead deployed on Trident II SLBMs. Congress, however, has repeatedly added funding through the National Defense Authorization Act, reflecting support from Republican legislators and some Democrats who view SLCM-N as essential to extended deterrence. The Fiscal Year 2024 NDAA directed continued development.
Critics, including arms-control analysts and several former senior military officers, argue SLCM-N would:
- Burden attack submarines with a nuclear mission, complicating conventional tasking.
- Blur the conventional-nuclear firebreak, since adversaries cannot distinguish a nuclear from a conventional cruise missile in flight.
- Duplicate existing low-yield capabilities.
For MUN and policy researchers, SLCM-N is a useful case study in executive-legislative tension over nuclear posture, the politics of tailored deterrence, and the broader debate over the role of non-strategic nuclear weapons in great-power competition.
Example
In the FY2024 National Defense Authorization Act, the U.S. Congress directed continued development of SLCM-N despite the Biden administration's 2022 Nuclear Posture Review recommendation to cancel the program.
Frequently asked questions
The W76-2 is a low-yield warhead on a strategic Trident II submarine-launched ballistic missile, while SLCM-N would be a cruise missile launched from attack submarines or surface ships, offering a slower, recallable, and regionally deployable option distinct from strategic SSBN platforms.
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