I've said this before, I'll say it again. Chris Christie, John Kasich, Ted Cruz, and Rick Santorum should all be asked to withdrawal from the presidential race because they have all defended Donald Trump. They clearly lack the intellect and judgement to be President, especially Cruz who has been Trump's biggest fanboy.
Asked by whom? Billionaires? Party "leaders" who've defended or stayed silent for Republicans far more odious than Trump? Doing that will just play into the narrative Trump is building.
The Republicans have spent Obama's whole presidency being trolls, and now they're getting beaten at their own game by a more accomplished troll.