We always hear that the US and USSR didn't want to fight in a direct war, because they feared WW3 would be nuclear war that ultimately will destroy human civilization through nuclear fire.
The US has had nuclear weapons since 1945 and the USSR since 1949. So I was wondering if there was a short time frame during the late 1940's or even early 1950's where they could conduct nuclear strikes against Soviet countries without the fear of full-scale nuclear retaliation that would result in the end of times or that the damage caused by the retaliation would at least be within acceptable boundaries.
Sorry if this is the wrong subreddit.
Technically yes, the United States had nuclear arms superiority for a very long time. However, politically it wasn't really possible without provocation, and the USSR never did anything to warrant such retaliation.
During the Cuban Missile Crisis, many (such as General Curtis LeMay) wanted the US to use the crisis as an excuse to launch an attack against the USSR because even though there would have been retaliation, we (the US I mean) still had way more weapons than they did.
Better to strike now and lose tens of millions than to wait until the Soviets caught up and lose many more.
Luckily that didn't happen.
The US had the ability to deliver small, isolated nuclear weapons onto Soviet territory as early as 1945. However they lacked the ability to do widespread nuclear bombing until after the Soviets had the bomb. The US air force analysts estimated that it would take well over 200 nuclear bombs to achieve a real "knock out punch" that would not just be some sort of conventional war mixed with a few nuclear detonations, and they didn't have that many bombs until the 1950s. Their delivery mechanisms (aerial bombers) were also a little insufficient (they were unreliable, could be shot down, etc.). So the US was wary about its nuclear superiority, especially since they also overestimated Soviet abilities to defend or deter.
By the 1950s the USSR was capable of striking targets in Europe or Asia but not the mainland United States. The US analysts did not entirely realize this, however, because they overestimated Soviet bomber capability. So they were in fact somewhat deterred even though in reality it would have been very hard for the Soviets to muster any kind of reply in kind to the US mainland. (For European allies, it would have been much easier.)
The Soviets did not really get the ability to threaten US mainland targets reliably until the development and deployment of their first ICBMs in the late 1950s/early 1960s. They were still outmatched considerably by the USA until the 1970s, which is when they were really at parity for the first time. But by the 1960s the Soviets could effectively threaten major US population centers and thus effectively deter.
The trickiest period in the establishment of the "nuclear taboo" in my mind is the Korean War, because it was a period in which the US could have plausibly used nuclear weapons without expecting any kind of reply in kind (the Soviets would not have nuked Europe just because Korea got nuked). Ultimately the US planners concluded that any military advantage would not be worth the risks and political opposition amongst allies.