Note on 8/29 at 3:40 PM: This article was written and published prior to Christie's speech.
To quote Ezra Klein: "This is a great speech. But it's a great speech for Chris Christie, not for Mitt Romney."
Let's assume that, like virtually every politician in America, Christie wouldn't mind being the president. He made a mistake not running this year, in which Republicans reluctantly nominated a former blue-state governor with low favorability to go up against a vulnerable sitting president. But economics counsels us not to make decisions based on sunk costs or regrets. Let's game this out.
If Romney wins in November, the soonest Christie could run is 2020, barring a historically disastrous first term for the former Massachusetts governor. First, he will have to decide whether or not to run for re-election in New Jersey in 2013. Many suspect that popular Newark Mayor Cory Booker will be the Democratic candidate, meaning Christie would face a bruising election. Losing would damage him nationally, and winning would require that he solidify his blue-state bonafides. This will make running for national office more difficult, even seven years later—just ask Romney.