The Arms Race and Mutually Assured Destruction

After 1945 the United States and the Soviet Union built nuclear arsenals that grew from a handful of bombs to tens of thousands of warheads by the mid 1980s. The point was not to use them. It was to make sure the other side believed they would be used in retaliation. This is deterrence: you avoid attacking someone who can hurt you back just as badly. The key piece is second-strike capability, the ability to absorb a surprise first strike and still have enough weapons left, on submarines, in hardened silos, on bombers in the air, to destroy the attacker anyway. If both sides have that, neither can win by striking first, so neither strikes at all. That standoff is mutually assured destruction, fittingly abbreviated MAD.

This logic explains why more weapons could mean more stability rather than less. It also explains the closest the Cold War came to breaking into direct war: the Cuban missile crisis of October 1962. The Soviet Union placed missiles in Cuba within range of most of the United States. For thirteen days the two sides edged toward nuclear war before Khrushchev agreed to remove the missiles in exchange for a public American pledge not to invade Cuba and a secret removal of American missiles from Turkey.

The arms race connects directly to decolonization and the wider Cold War, since both superpowers armed and funded proxy wars in newly independent states rather than fighting directly. It also sets up the problem of proliferation: once Britain, France, China, India, and others got the bomb, deterrence became harder to calculate, since any single actor's second-strike logic now had to account for multiple rivals at once.