This historical research study traces and analyzes the technological development and force deployment of US submarine-launched strategic nuclear ballistic missiles, and the evolution of their military missions - during and after the Cold War - from countervalue (civilian, political and economic targets) strategic deterrence to the wider range of strategic and theater-tactical nuclear/conventional military force targeting, characteristic of counterforce or warfighting capabilities. Scope of this study also includes: US nuclear ballistic missile submarine survivability against antisubmarine warfare operations, and the role of the US fleet ballistic missile force in current 21st Century regional and global military threat scenarios, and beyond.