I think he'll have a couple more months of staying power. He is tapping into the disaffected, anti-establishment element in the GOP far better than any of the other candidates are. He is causing the GOP significant damage by being associated with it, to be sure, but his supporters are the ones who think that the GOP is already damaged and don't want to waffle into the election with another Romney who only gives lip service to their views. He'll burn out eventually, but it will be at least a couple of months before he's gone.
In other really, really unbelievable news, of the $1.9 million his campaign has raised, only $1.8 million of it came from Trump himself. The rest of the money was from people who ... like ... donated to Donald Trump's campaign for President. Seriously. That happened.
And that's great because it's very likely that those people have blown their contribution wad. This Trump thing is by far the best thing that could have happened to Hillary. It's like a good NFC team battling their way to the Superbowl and then facing the lowest ceded AFC team who got there because the three teams they faced in the playoffs all lost their quarterback on the first play of each game.
After all of Hillary's struggles, she'll be able to stroll into the White House this time, provided Trump stays in it until the end. And he very well could. The idea that he could have a tremendous influence on the nation's highest office would feed his ego for at least 6 months. And that influence would last for generations. That's because the next President will likely be able to decisively tip the Court in their favor. It wouldn't matter if the influence was good or bad; what matters to him is that he played a key role in it.
