[Miss Marple]

I would have to know Rasmussen's description of "evangelical Christians." If he lumped in PCA, the United Methodists, and the United Church of Christ, he no doubt picked up a lot of liberals.

[HostileTerritory]

It's probably by self-identification. I don't know what that would do with the results. However, it's probably the same universe of respondents who voted 78% for Bush in 2004 and a high margin for Republican candidates in 2006 (unless I'm misremembering and that is white evangelicals.)