There is no could, unless something drastic happens he will not only win the nomination with a blowout, but will win the general election in a 1984 Reaganesque landslide fashion.
YOu will see the true color of the GOPe though when it becomes obvious he is going to win, they are going to do every dirty nasty underhanded thing to destroy him... they would rather have Hillary than this man.
As long as Trump is perceived as putting America First, he will continue to have huge support, even if congress stonewalls.
This is why Trump has the support he does, he is the only person who seems at his core to put America first.... period. Whether you agree with him or not, no one can seriously argue he is the only guy on either side of the aisle that is consistent in present what he wants as being America first, period.