Kevin Drum says something that I sort of agree with, but I think begs for some elaboration:
And while we're on the subject of why not a single Republican has announced a presidential candidacy yet — yep, that's the subject — isn't the answer obvious? It's because they all know Barack Obama is as good as a shoo-in in 2012. Unless something cataclysmic happens, the only reason for any Republican to run is either as a vanity candidate or to get practice for 2016.
"Shoo-in" is a bit of an overstatement, but it's true that incumbent presidents don't usually lose unless they screw up royally or unless the economy is headed down. Remember that even in Ronald Reagan's 1984 re-election of "Morning in America," unemployment was over 7 percent; what mattered was that it was heading down. And the economy is likely to continue to move in the right direction over the next year and a half, even if slower than we'd like, making Obama -- a pretty good campaigner, if you'll remember -- very difficult to beat.
There may be some candidates who actually do enter as practice for 2016, or more properly, to turn themselves into national figures positioned for such a run (if John Thune enters, that'll be the reason). But what about the others? Do they really think they're doomed? Of course not.
It's true that things can always change, and politics favors the bold. In 1991, George H.W. Bush had record-high approval ratings, and most everyone thought he was unbeatable, but some forward-thinking Democrats, particularly the governor of Arkansas, knew it couldn't last. Nobody thought a first-term senator from Illinois known for little more than making one good speech could go up against what everyone considered the most ruthless and effective political operation in American politics, but he did it anyway. And every candidate thinks that once people get a good look at them, success will inevitably follow.
Finally, being a politician -- particularly an out-of-office one preparing for a presidential primary -- puts you in a bubble from which the prospect of your eventual failure can be awfully hard to imagine. Yes, your pollsters may give you some problematic news every once in a while, but for the most part, you're surrounded by people constantly telling you how great you are. You go to a convention of conservatives, and people treat you like a rock star. You go on conservative radio and television shows, and the conversation is all about how right you are about everything, and how wrong your eventual general-election opponent is. You take your first gentle forays into meeting voters (primary voters, remember), and they seem really receptive, too. And finally, you believe the things you're saying: The country really is going to hell, and you really can save it. So of course the American people are going to agree with you. How could they not?
-- Paul Waldman