Intrade has another possible pick--Petraeus is trading at just under a ten percent chance at the Republican nomination.
This would be pretty interesting. Republicans have a long history of nominating war heroes and generals--basically every nominee from Eisenhower to McCain was a general, war hero, war President, or played a war hero in Hollywood. Bush 2000 and Nixon are a couple of exceptions. The military is one of the most admired institutions, and Petraeus in particular is highly regarded.
Moreover, unlike some past candidates--Colin Powell--Petraeus is fairly political. He's great with the press, worked some serious politics to get to where he is today, and is on the record as expressing interests in the Presidency. Sure, half of Congress probably has Presidential interests depending on the day of the week, but it's a little rarer in the military.
He isn't known for any sentiments on domestic policy, but that's exactly his promise. It means no long record of incriminating or flip-flopping statements, so can enter the campaign with a blank slate. People will project whatever they want onto him, so he can be all things to all people until he gets elected (sounds familiar...). I'm sure he's a smart guy--put him in the room with a few advisors, and he'll learn everything he needs to.
Of course, the nominee, and winner, in 2012 will be determined by future events we can't predict. But it is possible to sketch out the path in which Petraeus would do very well:
The economy keeps getting worse. Debt keeps rising. Obama exits Afghanistan, and things get worse there and in Pakistan. Terrorists strike somewhere. People perceive the government as corrupt and ineffectual; and its stance on national security as weak.
Petraeus steps in as the candidate of authority. His patriotism and competence are beyond question. It really doesn't matter what he says, as long as he comes off as reasonably intelligent and competent. This would be another Obama-like "branded" campaign, in which the overall image and tone of the candidate overshadows everything else. McCain tried to run something like this (Country First), and almost won (and would still have won if not for the post-Lehman collapse. I'm surprised I don't see more conspiracy theories/spite about that.).
Can you imagine trying to run attack ads against a successful war general? Not fun. All of the other potential Republican candidates have pissed off someone else in the camp at some point or another. Petraeus is arguably the only Republican alive who earns the respect, if not the outright adulation, of not only most Republicans, but many others as well.
Of course, if things turn out differently--the economy gets better, the wars end up going well--there will be much less space for a Petraeus candidacy. Either way, civilian-military relations seem be decidedly chillier under Obama, and it'll be interesting to see how this plays out.