But Rubio did more than than just make Christie’s point for him (though he did do that). Rubio also revealed that he hadn’t even bothered to prepare for the deeper accusation that he isn’t a man of his word.

Christie demonstrated on stage what many people have carried as almost a grudge against Rubio — that he believes he’s such a hotshot that he doesn’t need to earn voters’ trust. Simply by intoning the right phrases with the right pathos, he’ll ride to the White House on a crest of faith that, without him, the Republican Party cannot step into the future.

This is why Rubio’s Gang of Eight immigration reform dalliance keeps coming up. It’s not because virulent anti-immigrant sentiment has gripped the field (or the debate moderators), but because Rubio really believes he can leave his past political commitments in the same dust as the Bush-era GOP. He’ll be who he has to be to win — and you want to win, don’t you?