Reason  No. 5 : Race has been a surprisingly little-discussed topic — at least among politicians, in public — during the term of the first African-American president in American history.

But Obama's race has hovered over the politics of the last four years, in ways many on the left might point to in explaining his defeat.

It's with working-class white voters that Obama has struggled most in the polls.

He trails among whites nationwide and is losing by titanic margins in the South. Ohio, where Obama's auto bailout is popular, is a notable exception as far as white support for Obama is concerned.

Obama's race may not have hobbled him in the 2008 campaign, but if he cannot win another term, some in his party may at least partially blame it on once-dormant white resistance to the idea of a black president.