This was historically a Democratic union stronghold, but a more affluent constituency has moved into the area in the past two decades, making it a more competitive target for both parties.

CNN: Debate reaction from a hotly contested state

"Obama's win in 2012, despite the important Democratic constituency of young voters not participating at a high level, is good news, " said Michael McDonald, a George Mason University professor who specializes in voter turnout.

NPR: A Census First: Black Voter Turnout Passes Whites