Do I think Trump has any chance of winning the GOP nomination? Yes, though I would certainly bet against it. Do I think he has any chance of winning the presidency? A slim one, but not negligible. If he won the nomination, his credibility by that point would be considerable; and it's not as if the Democrats have a frontrunner currently whose viability looks to be assured going forward. But the likelihood that Trump would lose in a general election has sparked some genuine agonizing on the right, and it's kind of funny to watch conservative pundits suddenly embrace the pragmatic electability criteria they spent the past couple of cycles disparaging.Going forward: mark me down with Ezra Klein in regarding Trump as a genuine threat to American democracy
Mark me down also as disagreeing strenuously with those (including some I respect highly such as Virginia Postrel) who argue that John Kasich should drop out of the race on the putative grounds that this would make a Trump victory less likely. The way to stop Trump is not by rallying behind someone else who offers a diluted version of his terrible attributes, as Rubio does in his ideological shape-shifting and implicit promise to torture terrorism suspects to "find out everything they know."
Moreover, my concern about Trump is not that he'll go on to be the losing nominee but that, if he is the nominee, there is a chance that he might win the presidency. I would prefer a Kasich presidency over a Clinton presidency, but anybody now running --including Sanders and Cruz -- is manifestly preferable to the authoritarian potential of a Trump presidency.
Finally, I should add that I do share one thing with Trump and his supporters, which is that I now care little about the future of the Republican Party (of which I've been a member since 1983). A party that could get itself into this predicament is far from an indispensable bastion of anything worth preserving. The country does need alternatives to the Democrats, but right now the GOP mainly serves the purpose of making the Democrats look more attractive than they deserve.
UPDATED 2/26: I still would like Kasich to be the nominee, but I have to admit my opinion of Rubio has gone way up in the past 24 hours.
UPDATE: But not as much as my estimation of Chris Christie has gone down.