I can't speak to the situation in Oregon, but the population of Idaho is probably >25% LDS (I have seen numbers as high as 35%). Idaho is, of course, incredibly conservative. I think that the combination of this extreme conservatism and a familarity with the LDS religion makes it far easier for Mike Crapo to win in Idaho than, for example, in Massachusetts.
I think, in some ways, Nevada is also a special case, with Harry Reid being a Democrat. The evangelicals would be voting against him, no matter what.
With regard to Oregon, having lived all over, I will say that the effects of having drunk the Kool-Aid in the south seem stronger than in other parts of the country. Perhaps evangelical christians in Oregon are a bit more pragmatic than they might be in Alabama, for example.

Posted at April 28, 2006 8:28 AM in response to The Mormon Factor