From Tobin Grant here. He writes:
Beneath the Republicans’ regional split is Romney’s failure in states where the Republican base is made up of socially conservative evangelical voters. In New England and other states where evangelicals are in the minority, Romney has been able to win over the lion share of the evangelical vote. The result is a double-whammy for Romney: in states where the GOP is made up of more evangelicals, evangelicals are less likely to vote for Romney.