Contents of said letter from daily beast: https://archive.is/YFBK3#selection-773.0-779.748
“Dear Jonas,” the president wrote to Norway’s prime minister, Jonas Gahr Støre. “Considering your Country decided not to give me the Nobel Peace Prize for having stopped 8 Wars PLUS, I no longer feel an obligation to think purely of Peace, although it will always be predominant, but can now think about what is good and proper for the United States of America. Denmark cannot protect that land from Russia or China, and why do they have a ‘right of ownership’ anyway? There are no written documents, it’s only that a boat landed there hundreds of years ago, but we had boats landing there, also. I have done more for NATO than any other person since its founding, and now, NATO should do something for the United States. The World is not secure unless we have Complete and Total Control of Greenland. Thank you! President DJT.”
Apparently the USA militarily could no longer stop China taking Taiwan.
With Trump acting like this, China initiating that action becomes more likely.
I’m pretty sure that whether it can is irrelevant. Unter Trump it won’t because China playing strongman appeals to him more than petty things like allies and an independent semiconductor market. Also, he can very clearly be bought and Xi can just send him a couple yachts with tacky decor or something.