I've been reading John Mueller's excellent book, Atomic Obsession: Nuclear Alarmism from Hiroshima to Al-Qaeda. I just finished Chapter 3, "Deterring World War III," in which he argues that nuclear weapons weren't necessary to deter World War III because World War II was such a horrible experience for all concerned that the deterrence of war from the horror of non-nuclear war was about as great as the deterrence of war from the horror of nuclear war. In Chapter 3, Mueller has a colorful paragraph on Soviet Premier Nikita Khrushchev's stated views on war:
From the start, Khrushchev was clearly moved by the wars he had already experienced and had no intention of working his way closer toward a repeat of those calamities--much less a worse one. "I have participated in two world wars," Khrushchev wrote Kennedy at the height of the [Cuban missile] crisis, "and know that war ends only when it has carved its way across cities and villages, bringing death and destruction in its wake." In a speech to Soviet textile workers a year after the crisis Khrushchev recalled the loss of his son in World War II and the millions of other deaths suffered by the Russians, and then laid into his critics: "Some comrades abroad claim that Khrushchev is making a mess of things, and is afraid of war. Let me say once again that I should like to see the kind of bloody fool who is genuinely not afraid of war." The Soviet press reported that it was this statement that was cheered more loudly and wholeheartedly than any other by his audience. Or there was his earthy comment to some naval officers shortly after the crisis: "I'm not a czarist officer who has to kill himself if I fart at a masked ball. It's better to back down than to go to war." The Soviets never even went on a demonstration alert.
Disclosure: I received a zero-price review copy of the book from the publisher.
Update: I thought it went without saying but, from some of the comments below, maybe not. The Soviet Union lost just shy of 1/8 of its population in WWII. For the United States to lose the same fraction today would mean the death over 6 years of about 35 million people, or roughly an equivalent of the whole population of California.