Have you seen the polls lately? I mean, they were getting not fun there for a while, but Obama has really turned the old job approval numbers around. Where did this come from? A few thoughts.
1. Maybe people just needed to let off some steam. Apart from the Tea Party hard-core, I think the majority of the population hold two contradictory ideas in their heads: first, the economy sucks eggs and second, they like Obama. They like his personality and they like his program. So how do people deal with these two thoughts? Things are not fixed, but we like the guy trying to fix them. Well, they vote for his opponents in a mid-term election where he isn't on the ballot. Once they get that out of their system, they go back to liking him. Imagine you're a boss who's given a super-hard, vital task to a trusted underling. The job isn't done, but your guy is brilliant and no one could have done better. What can you do? Well, you yell at your underling a bit, but keep him on the job and give him a raise in a few months. That's the midterm results, followed by a big bump in Obama ratings.
2. Theory the second: This is all positive feedback from the lame-duck session of Congress. Obama got a whole slew of great headlines by passing and signing a whole slew of legislation: tax cut deal, ending don't ask don't tell, passing the START treaty and so on. Which means that Republicans were.completely right, tactically speaking, to block as much as they did. Just imagine if Obama had gotten those headline and that bump before the midterms? We might still have Madam Speaker.