if Trump could unite the nation, then democrats are also included, democrats also believe in making America great, even could be concluded as the common denominator of both parties, and Trump have the same goal, his success would unite the USA eventually.
The last laugh is a long way off. Now we get to find out if he can handle being president (though how long before we know, is hard to say, I guess we'll know within a year if he's really bad). If not, then it's the rest of the world that gets the last laugh, at how dumb we were to elect such a clown.
