A regional split:

Obama is outperforming any Democrat back to Jimmy Carter among white voters, getting 45 percent to McCain's 52 percent. But in the South, it is a very different story. Obama fares worse among Southern whites than any Democrat since George McGovern in 1972.

Whites in the East and West tilt narrowly toward Obama (he's up 8 and 7 points, respectively), and the two run about evenly among those in the Midwest. By contrast, Southern whites break more than 2 to 1 for McCain, 65 percent to 32 percent.

It's Christianism.

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