In 2008, Obama won a decisive national victory with a diverse coalition of young, minority, college educated, and non-southern white voters. Four years later, Obama’s once-broad coalition has collapsed—but his losses aren't spread equally across a diverse electorate. Obama continues to hold near ’08 levels of support among black and Hispanic voters, but trails Romney by a historic margin among white voters, and particularly white voters without a college degree.
With Obama’s losses manifesting unevenly across his diverse coalition, a surprisingly diverse set of battleground states are moving in Romney's direction at very different speeds. The 2012 battlegrounds range from lily-white Iowa, where 86 percent of Obama’s supporters were white in 2008, to North Carolina, where more than 40 percent of Obama’s supporters will be African Americans. Latino voters will approach 20 percent of the electorate in a state like Nevada, but might not play a discernible role in Ohio. Obama needs a strong showing in the affluent, well-educated, and post-industrial metropolitan areas like Denver, Raleigh, Washington, but his hopes in Ohio depends on the white working class voters in the old manufacturing hubs of Youngstown, Cleveland, and Toledo.
Predictably, changes in the composition of Obama’s coalition over the last four years voters leave him struggling in states where he was most dependent on the support of whites, but doggedly resistant in states where he benefited from demographic changes and improved performance among Latinos and African Americans. Obama won Iowa, Wisconsin, and New Hampshire by double digits in 2012, but he only maintains a slight lead in all three states. In contrast, his strongest battleground state is Nevada, a state Bush won in 2004, but where a growing Latino population offers Obama the promise of a clean victory. And North Carolina voted for Obama by less than one-third of 1 percent in 2008, yet the battleground state with the largest African American population remains close in 2012. North Carolina and Wisconsin were separated by 14 points four years ago, but the most recent polls show that the gap between those two states has diminished to as little as six points. There's a simple reason why the gap between North Carolina and Wisconsin has been cut in half: Obama is twice as dependent on white voters in Wisconsin as he is in North Carolina.
Over the last four years, the battleground states moved predictably according to their demographics with just one exception: Ohio. The Buckeye State is as white and working class as its reputation would suggest. In 2008, 74 percent of Obama’s supporters in Ohio were white and 43 percent were whites without a college degree. But while every other battleground state has clearly moved in Romney's direction to an extent roughly proportionate to Obama's previous dependence on white voters, Ohio hasn’t budged—Obama won by 4.7 points in ’08, and he holds a 2 point lead today, despite the state’s traditional Republican lean.
One way to illustrate the extent that Obama is outperforming demographics in Ohio is to simulate how each of the battleground states would vote if their white voters shifted proportionately and uniformly toward Romney to the same extent as the national polls.* Under this scenario, one would expect Romney to win Ohio by 4.6 points—6.5 points better than his actual 1.9 point deficit in the Pollster average. No other state deviates so much from the projection—its nearly twice as much as much as Iowa, the next state on the list, and one of the few states where McCain spent nearly as much as Obama in 2008. On average, the projection suggests that Obama is outperforming expectations by 2.15 points in the battleground states—not new information to those who have been comparing the national and state polls. But more than one-third of that is attributable to Ohio—otherwise Obama is only outperforming the projection by a more modest 1.5 points, which I think is pretty decent for an abstract calculation based on the exit polls.
Over the last four years, Obama's support among white voters has fallen to historically low levels nationally, predictably rejiggering the battleground states along racial lines. But the wave has completely missed Ohio, where Obama continues to hold a slight lead in a traditionally Republican, white working class state that only voted for him by 4 points in 2008. Other than Florida, Obama couldn't have chosen a better state to defy demographic expectations than Ohio, and at the moment, it's responsible for his clear advantage in the Electoral College.
*The actual assumptions for national numbers: 35 percent with white non-college voters, 42 percent with white college-educated voters.