[user104658]

Originally Posted by Oliver_W

Sounds rather petty. The USA is one of the big players, so to leave them out because its leaders has said mean things is like hewing off your nose to upset your face.

It's not really that simple though; it's mainly for the discussion of trade and Trump has made it clear that his policies are going to be increasingly isolationist and he doesn't really want to trade with anyone more than absolutely necessary. What is there to discuss?