One of the numbers that hasn’t gotten much attention from the exit polls is President Obama’s job approval. According to the exits, it was an astonishing 54 percent. Maybe that number is off. Maybe it is a function of who showed up to vote. But if we accept that it’s roughly correct, it says a lot. If we had known a year ago that Obama would have a 54 percent job-approval rating, we probably would have said he couldn’t be beaten.