It is conventional wisdom that the Bomb prevented the cold war going hot but there is at least an equally strong argument the opposite way. Without the Bomb in 1945 the USSR was no threat whatsoever to the US & the US only a minor one to the USSR. There was no real conflict between them, The propaganda is that the USSR would have tried to occupy all of western Europe but purely on logistics that would be improbable. Perhaps without the cold war France & Italy might have voted communist but so what – they would have been French & Italian communists just as Tito & Mao were Yugoslav & Chinese communists. The Russians did keep an enormous army in Eastern Europe which was the justification for western fears but the USSR thought this was its only counter to the threat od American Bombs. Both sides held knives to each other’s throats because both feared to be the first to sheath them but neither would have been scared if the weapons hadn’t been so sharp.