If Republican Richard Nixon was able to go to a nuclear-armed Communist country threatening to annihilate us..?

The cirstances were different in nixons day. The soviet union and China had a falling out. The Chinese were tired of the racist attitudes of the russians, plus they were also tired of Moscow trying to dictate to them how to run their country. So Nixon took advantage of this break. When Hungary and Czechoslovakia tried to break from Moscow, Moscow ran over them weith tanks because theyre small countries. China on the other hand way outnumbered the russians and so couldnt so easilly be invaded.