The US nuclear forces modernization program has been portrayed to the public as an effort to ensure the reliability and safety of warheads in the US nuclear arsenal, rather than to enhance their military capabilities. In reality, however, that program has implemented revolutionary new technologies that will vastly increase the targeting capability of the US ballistic missile arsenal. This increase in capability is astonishing- boosting the overall killing power of existing US ballistic missile forces by a factor of roughly three- and it creates exactly what one would expect to see, if a nuclear-armed state were planning to have the capacity to fight and win a nuclear war by disarming enemies with a surprise first strike.
The revolutionary increase in the lethality of submarine-borne US nuclear forces comes from a ‘super-fuze’ device that since 2009 has been incorporated into the Navy’s W76-1/Mk4A warhead as part of a decade-long life-extension program. We estimate that all warheads deployed on US ballistic missile submarines now have this fuzing capability. Because the innovations in the super-fuze appear, to the non-technical eye, to be minor, policymakers outside of the US government (and probably inside the government as well) have completely missed its revolutionary impact on military capabilities and its important implications for global security…
The W76 upgrade reflects a 25-year shift of the focus of US hard-target kill capability from land-based to sea-based ballistic missiles. Moreover, by shifting the capability to submarines that can move to missile launch positions much closer to their targets than land-based missiles, the US military has achieved a significantly greater capacity to conduct a surprise first strike against Russian ICBM silos…
In spite of its severe limitations, this growing defense system could appear to both Russia and China as a US attempt to reduce the consequences of a ragged Russian or Chinese retaliation to a US first strike against them.
We cannot foresee a situation in which a competent and properly informed US president would order a surprise first strike against Russia or China. But our conclusion makes the increased sea-based offensive and defensive capabilities we have described seem all the more bizarre as a strategy for reducing the chances of nuclear war with either Russia or China…”
-Hans M. Kristensen, Matthew McKinzie, Theodore A. Postol from The Bulliten of Atomic Scientists