“Nixon’s opening to China may have been good cold war politics...”
And that’s probably not even the case as far as history.
Nixon did this in large part to gain a two state solution for Vietnam. He and Kissinger considered it a trade of Taiwan for S. Vietnam.
Well, Taiwan got derecognized by the US and international community, which is what the Chinese wanted, but S. Vietnam did not survive, which is what we were supposed to get.
I’m not so sure China was in a position to deliver Vietnam. But what did happen was increased pressure on the Soviet Union, which was another of Nixon’s goals.