With Obama struggling among independent voters and Democrats likely to constitute a slightly larger share of the electorate than Republicans, Romney will probably carry independents in a close national election. That doesn't mean the effects will be the same across the electoral map, though: Since independents aren't distributed evenly across the country, Obama's dependence on independent voters varies considerably by state.
Regardless of whether we consider all independent voters or just white independent voters, self-identified independents constituted a far greater share of Obama's coalition in the North and Midwest than in the South and Mid-Atlantic. In states like New Hampshire, independents constituted an unusually large share of the electorate; not only that, but Obama carried a clear majority of them. Partisanship increases along with African Americans and white evangelicals as one heads further south, where both candidate's chances dependent more on turnout than the disposition of a marginal number of swing voters.
Even though Obama seems to have lost considerable support among white independents, there is not a convincing relationship between Obama's losses since 2008 and his previous dependence on independent voters. For example, Obama hasn't suffered undo losses in New Hampshire, despite being the state where he was most dependent on independent voters.
Although a few outlying states prevent a remotely compelling correlation between Obama’s losses since 2008 and his dependence on independents, there is still a rough pattern: Obama was more dependent on white independents in states where he relied on the support of white working class voters.
If you compare Obama’s dependence on white working class voters and independents, Colorado stands out as the only state where he was particularly reliant on white independents, but not white working class voters. That might help explain why Obama has lost more ground in Colorado than his relatively low dependence on white working class voters might suggest.
At the same time, the Mid-Atlantic stands out—again!—as the region where Obama would be most likely to hold his gains from 2008. To illustrate just how resilient Obama might be, consider this: If Obama lost a staggering 20 percent of support among white independents, it would reduce his share of the popular vote by just one percentage point in North Carolina.
Independents and white Independents are broad categories that obscure considerable underlying diversity. But to the extent that independents might be expected to behave similarly across the country, weakness among independents—and particularly white independents—could subtly alter the electoral map. In states like New Hampshire and Colorado, losses among white independents would have big consequences, even while Obama's coalition holds in North Carolina.