Hmmm ... AFAIK Gen. McArthur did advocate for using nuclear weapons on China during the Korean War (note that China did not have nuclear weapons at that point).

Hmmm ... AFAIK Gen. McArthur did advocate for using nuclear weapons on China during the Korean War (note that China did not have nuclear weapons at that point). And Nixon tried to give the impression he was crazy and might use them in order to pressure the other side to end the Vietnam War; he even flew bombers toward (the USSR, I think); but that gambit failed. On the other hand, it's easy to imagine that the US and USSR soldiers directly fighting and killing each other could escalate more easily than the US fighting Vietnamese troops or the USSR fighting Afghans.