For the GOP, Chris Christie is on the leading edge of politics, the most broadly acceptable captain of a change movement that the Republican Party can embrace. That makes him the de facto leader of red state America, even if it's not willing to accept him just yet.
One of my favorite axioms of presidential politics is that the times choose the (wo)man; the (wo)man does not choose the times. In change elections, a solid mass of voters tend to side with history, and they often choose the candidate whose personal qualities least remind them of what they're voting against. President Obama's new demographic coalition might signal a change in this formulation because it has become much easier to turn out particular kinds of voters regardless of whether they are intrinsically motivated.
Obama's anti–Iraq War advocacy appealed to a Democratic electorate primed to hear one. In the general election, he campaigned on a near-complete break with the foreign and economic policies associated with George W. Bush. Christie has sent signals to everyone that he intends to run for president. His tone is perfect for the times: he wants to get things done. He's not interested in picking ideological fights. His manner is brusque and unvarnished, but not unpolished; his deliberately cultivated everyman personality lines up nicely with what he has done as a governor. He knows when to put the knives down and embrace a president who is popular in his state. On a day-to-day basis, his walk backs up his talk.
Economically, Christie's policies have been typically Republican: spending cuts, property tax caps, bashing unfair advantages for public employees — but he is not an anti-tax dogmatist or an advocate of draconian spending cuts. His watchword is truly commonsense conservatism with regard to government. He wants it to work; he thinks there is a role for it, a big one. New Jersey's governor is uniquely powerful; the state's tax system is uniquely awful, unfair to both businesses and individuals; a little reform can build a lot of credibility with voters. At the same time, he has ideas about its role that will meaningfully differ with the Democratic presidential nominee.
There is nothing he has done — not one thing — that would render him unacceptable to a majority of the 2016 electorate. (Yes, he's against gay marriage. He's made it clear, by his actions Monday, that he is not prepared to litigate the issue nationwide, that he understands his personal views are on the wrong side of history, and that he will not expend political capital on an ideological crusade in order to please the Republican base.) If the GOP primary sorts out into a Ted Cruz–Rand Paul revanchist wing and a commonsense governing conservative wing, Christie can probably make it through the gauntlet of the GOP nomination contest. And about his size: it still marks him as a regular guy, and his surgery to reduce it is probably enough to satisfy any lingering concerns about his hardiness.
He might not run.
He might face a steamroller in Hillary Clinton.
He might find himself enveloped in a major scandal. (If you listen to Sean Hannity's radio program, Hannity certainly seems to think that there is a lot of untilled dirt out there.)
But right now, he's probably the best thing going for the GOP.