Only way Trump gets re-elected will be if the economy remains firing on all cylinders. I see the FED working against him, along with the media and the elites of both parties. If the economy is slowed down, he will struggle to get re-elected.
I believe HRC enters the race, wins the nomination quickly and challenges Trump in a real race. Economy good - Trump wins; economy bad or slowing, she has a shot.
This is not a lock for Trump. Plus, he could bail, and say enough is enough. I think Romney is banking on that plus any reason to not have Trump running for him to step in. Cruz would run too. And the moron from Ohio, John Kasich, the mailman's son. And let's not forget about Little Marko!