Everything that Donald Trump puts out there is like a "trial balloon" to gauge public opinion and provoke outrage. There is always a kernel of truth in whatever he says and also to see how far he can push things. Even if we play devil's advocate and let say that Canada wanted to be the 51st state (wtf, it's 10 provinces and would be ten new states so 60 states and then there is Greenland too... but I digress). I honestly believe in his head he wants to annex Canada and nobody is there to tell him that's a bad idea. Same with Greenland and probably parts of Mexico too. But even if he got his wish, he would be long dead before anything would happen and the next president will likely kill any plans. But when there are no adults in the room to tell the lunatics they can't do the crazy shit, then this is what you get. Actually, I think we will see military incursion into Mexico. Trump wants to do something dramatic and drug lords are an easy target and nobody is going to stop him...