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Trump will win the nomination but then be soundly beaten by Clinton in the actual contest. Along the way he will destroy the Republican Party by tearing it apart. "
That is how it is looking. However, Trump is, presumably, not as dumb as he appears. He has, it seems to me, decided that as a political outsider the best way of making an impact is by adopting a loud, confrontational style. That's worked very well so far with a lot of Republican voters, but has outraged the party to the extent that many leading Republicans have declared that they will openly oppose him come the election. If that happens, Trump is doomed. He can't win a presidential election like that. So at some point he'll have to change tack, and rein in his more outlandish, and even less outlandish, pronouncements. Then again, the problem for him will be that he may disappoint the "ultras"" and those voters who see him as "anti-establishment" (some of whom have been putting Sanders down as their second choice for President, for example.)
Either way he does seem doomed to lose, but it will be interesting to see what shape the already troubled Republicans end up in afterwards.