First, Jan Crawford at CBS writes about how on election day the Romney campaign expected to win:
"They thought intensity and enthusiasm were on their side this time - poll after poll showed Republicans were more motivated to vote than Democrats - and that would translate into votes for Romney."
"They misread turnout. They expected it to be between 2004 and 2008 levels, with a plus-2 or plus-3 Democratic electorate, instead of plus-7 as it was in 2008. Their assumptions were wrong on both sides: The president's base turned out and Romney's did not. More African-Americans voted in Ohio, Virginia, North Carolina and Florida than in 2008."
"Undecided voters. The perception is they always break for the challenger, since people know the incumbent and would have decided already if they were backing him. Romney was counting on that trend to continue. Instead, exit polls show Mr. Obama won among people who made up their minds on Election Day and in the few days before the election."