I found this post by Kevin Drum pretty interesting, because it ties into something I've been thinking with regard to Obama for a long time now. I genuinely can't remember whether I said anything aloud about it during the presidential campaign (and if I didn't, it was an opportunity wasted), but I noticed that both with Clinton and (especially) McCain, Obama ran slow-burn campaigns that built to absolute knock-out punches. Sure, the financial crisis kicked in just as McCain was trying to argue the country was doing well, and that gave Obama plenty of material with which to work with, but in both cases his supporters spent weeks or even months whining he wasn't playing the extremely strong hand he had in the wake of the Bush administrations myriad failures and Clinton's apparent refusal to see that the system needed fixing, and not gaming. 
In the end, after a period of simply weathering attacks by playing tight-lipped defence, Obama would change tack, savage his opponents, and watch his poll numbers spike. The two dominant narratives at the time were based on the questions "Has Obama finally learned how the game is played?" and "Will it be too little too late?". What I saw almost nothing of was the possibility that this was a deliberate strategy. Spend some time getting knocked around, and not really dignifying the attacks with a response (the notable exception to this during the campaign was his speech clarifying his "clinging to guns" remark, but that seemed more about fixing his mistake then defending himself against his opponents piling on), watch as the attacks get more aggressive, far-fetched and, frankly, borderline-racist, and then return fire, starting with an ad or a brief comment here and there before moving into full-on attack mode, and riding the poll-spike into victory. It's political rope-a-dope; by the time you move into the endgame your opponent's attacks look either tired (Reverend Wright) or increasingly crazy (secret Muslim), and are turning into white noise. Once you launch the fight back, it's something new, so the news outlets are more likely to carry it, you start to dominate the discourse, and rather than fire up your base at the very start, you do it at the exact moment it matters most.
It's not a strategy without risk, of course; if you leave it too late your spike might not arrive in time, or might not compensate for the numbers you might have lost waiting around (for all the complaints so many Americans have about partisan politics, they seem awfully willing to act in ways that maximise the effectiveness of petty bickering). It's also true that this strategy may not work as well for a piece of legislation as it does for a candidate. I just thought it's worth noting that Obama has previous with this particular line of attack .
 Obviously, Obama is playing the system now, and I doubt he ever intended to do things any differently. But the perception that he was going to change the way things were done was sufficiently strong for him to use it as an effective campaign tool.
 The alternative reading, that Obama is just slow to react to attacks and that he's been lucky so far, can't be dismissed either, though I would point out that the man is clearly not an idiot, which is what he would have to be to have been a Senator during the Bush years and not worked out how Republicans play the game. Still, the alternative possibility certainly seems to be Steve Benen's take on it, at least this time around.