This election is not what was expected. Krugman speculates it might have to do with healthcare:
A brief, mostly subjective note: This really isn’t looking like the election anyone expected. Obviously it’s not the election Romney and the Republicans expected and wanted; but it’s also looking very different from what Democrats expected.
What Romney & Co. expected was a simple rejection of Obama because of the weak economy. As Greg Sargent often reminds us, this isn’t how it has played at all. On one side, voters tend to react to recent trends, not the absolute level — and the economy has gotten better in some ways over the past year, though obviously not by a lot. On the other, people do remember the crisis of 2008, which they still blame on Bush, and remain willing to cut Obama substantial slack.
And let me add a speculation: I suspect that in the end Obamacare is turning out to be a big plus, even though it has always had ambivalent polling. The fact is that Obama can point to a big achievement that will survive if he is reelected, perish if he isn’t; health insurance for 50 million or so Americans (30 million from the ACA, another 20 who would lose coverage if Romney/Ryan Medicaid cuts happen) is enough to cure people of the notion that it doesn’t matter who wins. NYT