One of the main reasons why the US rose to prominence after WW2 was a series of alliances and treaties with various countries all over the world. In only two years, he undid decades of work.
Frankly, I'm not even mad that he did, the whole western world turned a blind eye to the shit America has been doing for decades because its "in all our interest". I don't know what this new world looks like where we aren't all living under the US foot, but I'm pretty sure it'll be better.