It was the urban vote says Nate Silver:
…the future of America is an urban one — among the twenty largest metropolitan areas in 2000, nineteen had added population by 2007, a trend likely to sustain itself as rising gas prices place more pressure on exurban commuters. Republicans trail Democrats among essentially every fast-growing demographic except the elderly — the youth vote, the Latino vote; they never had the black vote. It is long past time that they hone their pitch to urban voters, and find their shining city upon a hill.
The Dish 