With his insulting Tweets and derogatory remarks, Trump is creating local pressure and strong incentives for foreign politicians not to negotiate anything with

With his insulting Tweets and derogatory remarks, Trump is creating local pressure and strong incentives for foreign politicians not to negotiate anything with him. That doesn't seem very productive. And that is on top of some already existing massive unpopularity. Take Mexico, for example. Making derogatory remarks about a whole country and its people makes it almost impossible for any politician of that country to negotiate without risking to loose a substantial amount of voters. It's a real diplomatic problem, which is aggravated by the fact that many countries are still trying to figure out whom they can reach in the US diplomatic chain in order to get any reliable reply.