"I'll stop short of predicting that a third-party insurgency will ultimately happen.
"But it seems obvious that it could deny Trump the White House. And for that reason, the threat of a third-party challenge may be the conservative movement's strongest piece of leverage over a man who seems to be thwarting them at every turn. As long as Marco Rubio or Ted Cruz could still win the nomination, a third-party plot might cause Trump to reverse his own loyalty pledge in the event he loses. But if and when Trump has the nomination clinched, I expect, at the very least, that movement conservatives will make a lot of noise about a third-party challenge. It may be their last best chance to wrest concessions from the billionaire."
Conor Friedersdorf at The Atlantic asks, "Would conservatives dare to greet a Trump victory with their own third-party challenge?"
David Corn in Mother Jones writes that Republican leaders are reaping what they have sown with Trump.
And Philip Rucker and Robert Costa depict in The Washington Post depict the "Republican Party's Implosion."