When I was part of the Quaker US/USSR Relations Committee in the 1980s (my first Quaker project), I visited the Soviet Union many times and was blown away when Reagan went to Moscow and made friendly overtures to Gorbachev. He even gave him as a gift a copy of the movie "Friendly Persuasion," stating that this is a classic American film about the conflict of conscience during times of war and shows that "Quakers have a better way." Reagan's meeting with Gorbachev was historically significant because Reagan was a well-known anti-Communist and Cold Warrior, and no one questioned his motives or his integrity. As a result, Reagan was able to negotiate an important nuclear reduction treaty and helped to end the Cold War. Even though I disagreed with Reagan on most issues, I had to give him credit for doing the right thing when it came to the USSR.
Similarly, when Nixon went to China and opened up diplomatic relations, it was historic because Nixon had similar credibility. Both Republican Presidents were able to do what a liberal Democrat would probably have found politically impossible because Republicans were have accused them of being "soft on Communism" or worse, a traitor.
Trump is a very different breed of Republican president from these two men. Because his staff reached out to the Russians, apparently to find dirt on Clinton, and because the Russians clearly interfered in the election, Trump is compromised. No one knows for certain what kind of dark secrets are lurking in his tax returns or in some Russian espionage agency's file. All we know is that Trump is in a state of denial that makes him look ridiculous and out of touch with reality. This will make it difficult, if not impossible, to be an effective deal maker.
He is similarly compromised in his relationship with China After making outrageous accusations against China during the campaign, he now allows himself to be flattered and cajoled by Xi Jinping, who is in a much stronger political position than Trump. Trump is in a weaker bargaining position than any previous President in part because he has savagely cut the diplomatic corps he needs to be effective.
It is sad to see America declining as a world power because Trump is ignorant of what it takes to be a world leader. The only thing he seems capable of is selling weapons. As a result, the US has become not the leader, but the arms dealer of the world. How sad!