Then the bridge thing happened and, despite a brief uptick at the beginning of this year, Christie was finished. On Wednesday, he told aides that he was leaving the race, The Washington Post has confirmed.
Christie is now the fourth of the seven Republicans who have at some point led the field in the Real Clear Politics polling average to drop out. Christie led in early 2014, followed by Paul (gone), Mike Huckabee (gone), Jeb Bush, Scott Walker (gone), Donald Trump and Ben Carson, who's now hanging on by a (very expensive) thread.
Even before Christie's departure was finalized, Carly Fiorina's became official. She never reached the same level of support as Christie, but made a strong surge at the end of 2015, based on her performances in the first two debates. It didn't last. It was of the boom-and-bust style we grew accustomed to in 2012, though the boom was never really a threat to overtake the leading candidates.
The graph below, showing the national polling average back to mid-2013, shows Fiorina's spike and Christie's slow erosion clearly.
You can also see Christie's death rattle from January, when he suddenly gained traction in New Hampshire, and just as suddenly saw it fade. Like Fiorina nationally, he had a moment in the state — and that moment passed.
The two moderate candidates pinned all of their hopes on New Hampshire. Christie came in sixth; Fiorina, seventh.
It's remarkable that Christie actually lasted into February. Over the course of the past few months, his favorability rating, badly damaged by the bridge scandal, recovered a bit. In another year, that might have helped. But this is the year of Donald Trump, and it didn't.