Jeffrey LewisSLCM Data Exchanges Revisited

Regular readers know that one of my hobby horses is that the US and Russia should revive the sea-launched cruise missile data exchanges that expired with START as a confidence-building measure because the next agreement will probably have to say something about SLCMs.

A short version of my proposal appears in a new Carnegie monograph, Beyond Treaties: Immediate Steps to Reduce Nuclear Dangers. (Beyond treaties isn’t quite right since, at least in my case, the confidence-building measure is designed to make possible a future treaty.)

You should check them all out, especially the proposal by Linton Brooks on “Joint Experiments and Studies.”

The full text of mine is after the jump.


The Obama administration intends to seek, in the next round of negotiations with Russia, an agreement that would “include both non-deployed and nonstrategic nuclear weapons.” Administration officials call this approach the “whole enchilada.” Republicans, too, have strongly pressed that any future agreements address Russia’s tactical nuclear weapons.

One of the more difficult problems in the negotiations over the original START—and one that will need to be resolved in any arrangement that covers tactical nuclear weapons—relates to long-range sea-launched cruise missiles (SLCMs). Although the United States has now retired its last nuclear-armed SLCM, there are concerns that Russia still deploys them and some evidence it may build a new system. Any future agreement will need to account for these weapons.

The United States and Soviet Union ultimately agreed to exclude SLCMs from START, instead issuing “politically binding” declarations under which the parties would deploy no more than 880 nuclear-armed sea-launched cruise missiles aboard naval vessels and declare, on an annual basis, deployments for each of the next five years. These exchanges ended with the expiration of START in 2009. Such a solution will not be possible under a comprehensive agreement that seeks to account for every warhead.

Nonetheless, a useful near-term confidence-building measure would be to resume the data exchanges under a politically binding agreement identical to the one that lapsed with START. The parties could use the same text that had been developed as part of the START process, even if the limit of 880 deployed nuclear-armed SLCMs is too high. (If Russia insists on declaring all long-range SLCMs, a new limit high enough to avoid interfering with conventional operations would be required.)

The resumption of data exchanges could be the first in a series of confidence-building mea- sures related to SLCMs. New START includes provisions for tagging sea-launched ballistic missiles and intercontinental ballistic missiles with a unique identifier and for staging exhibitions of treaty-limited items converted for conventional use. Further confidence-building measures could explore how these provisions could be extended to deal with SLCMs. Such measures would contribute to any agreement that constrains Russia’s tactical nuclear weapons, whether it is the form of the “whole enchilada” or something more limited.

Jeffrey Lewis is the director of the East Asia Nonproliferation Program at the James Martin Center for Nonproliferation Studies.


  1. Pavel (History)

    Confidence-building is a great idea, but with this one it’s not quite clear why would Russia ever agree to this kind of exchange. The START exchange was agreed on at the time the U.S. has nuclear SLCMs – this is not the case anymore. As for conventional missiles, if anybody in Russia would want a number to make a point that conventional SLCMs are a threat to Russian strategic forces or something like that, they would just pick the highest estimate available.

  2. Ken Macaulay (History)

    Is there a push on the US side to stretch this further than Russia, as I seem to recall reading that one of the stumbling blocks was that the Russians wanted other major nuclear powers involved & their deployable weaponry taken into account in future arms reduction talks.

    RE: SLCM’s & cruise missiles in general – is there some kind of formula in arms-control to identify only nuclear capable missiles that would take into account upload potential? ie. which missile types can modified to be fitted with a warhead, & how many launch platforms are available for them?

    • George William Herbert (History)

      Any extant SLCM is payload volume/weight-wise nuclear capable…

  3. George William Herbert (History)

    Regarding Jim Acton’s bit on whether conventional cruise missiles can threaten silos –

    Yes, but with their stock warheads perhaps not.

    The few bulk penetrator cruise missile warheads out there are possibly another story.

    Designing a dedicated superhard target buster warhead, using EFP or shaped charge principles, is a definite yes in the warhead performance realm (from standoff, could probably penetrate 2+ meters of RHA, tens of meters of reinforced concrete). Probably yes in terms of targeting systems being able to point the warhead axis at the silo center and detonate on time.

    I see no sign anyone did that already, but that’s different from “can’t be done”. The tools for developing those warheads are available, it’s just a few man-years of engineer, few tons of explosives and few development and test firings worth of test setups.

    • Jeffrey (History)

      I believe the National Academies study on conventional strike includes a recommendation for an improved conventional penetrator.

    • Cthippo (History)

      Even if it didn’t penetrate the silo, it seems like a couple of tons of high explosive going off at the surface would break something important enough to keep the missile from launching.

      I know that the US silos are theoretically hardened enough to survive a nuclear near miss, but will all the stuff inside still work well enough to launch? Has the actual capacity to launch following a conventional hit or nuclear near miss been demonstrated reliably?

    • George William Herbert (History)

      I don’t know all the test details, but they’re shock hardened. They were supposed to function after a nearby nuclear weapon, not just have a functional missile left inside afterwards – either one without the other is a mission kill on the silo.

    • Moe_DeLaun (History)

      This DARPA program could transform the idea of “conventional munition.” A large MAHEM warhead on an appropriate Prompt Long-Range Strike platform would make quite a silo-killer.