From NYT's The Caucus:

In interviews as they walked out of the polls, 37 percent of voters said that one reason for their vote was to express opposition to Mr. Obama. That is 13 percent higher than the number who said their vote was an expression of support for the president. And as noted by Dalia Sussman, polling editor, it's hardly different from the numbers in 2006, when anger at President George W. Bush and the war in Iraq motivated more voters, by a margin of 14 percent, to say their vote was a protest against Mr. Bush.

Soooo... who to blame? Dumb voters or dumb Obama for cutting himself off from the voters, and failing to articulate what he's actually accomplished?