You have to go back to Wilson in 1916 to find a re-elected president who had less of the popular vote than in his first election. Wilson's second term was a catastrophe and it is not much of a jump to foresee that Obama's will also be. In his first two years Obama had a super-majority and was unable to convince members of his own party to work with him. I don't see much prospect of a lame duck president without a mandate being able to do any better in his second term. If you think Bush had problems in his second term, you ain't seen nothing yet.