Nuclear weapons deter by the possibility of their use, and in no other way. Although US and Soviet arsenals became grotesquely excessive in both numbers and diversity in the late 1960s, by the later 1908s there had been very extensive reductions in both numbers and types. NATO's collective doctrine had accepted that the only sen-sible role for its nuclear weapons was for war-termination. Western governments had increasingly accepted the idea of sufficiency, recognizing that notions of nuclear supe-riority were vacuous.