In the calculus of history, nuclear weapons have ironically kept the world a safer place, at least until now.
The Soviet buildup of hundreds of divisions during the Cold War was ultimately stayed not by the dozen of so US and Allied divisions opposing them in West Germany but by the threat of unleashing US and British tactical nuclear weapons if they attacked. The Soviets were evil but they were sane as well and they understood that Europe in a nuclear ruin would serve them no good.