Trump pulled out of pretty much every deal and treaty Obama had made and started trade wars with US allies. This has made diplomacy significantly harder for the US because now we all know that any deal we make with the US is only good until possibly the next election. This means it will be harder for the US to make any deal with any nation and the US are as reliant on global trade as everyone else. It’s similar to Brexit where the UK leadership basically told all their allies to eat shit. It’s going to be a while until they get any good deals with the EU.