With Bush's approval ratings reaching historic lows -- what one GOP spokesperson, with admirable understatement, calls "a challenging political environment" -- the question arises: who is holding on to support our beleagured president and his party?

According to a recent Pew survey, one group is remaining loyal more than any other: white evangelicals. While support for Bush has fallen among this group, they're still his biggest fans. Perhaps most importantly for 2006, they're also still keeping their faith in the GOP:

A new analysis by the Pew Research Center finds that while the president still has the support of a majority of white evangelical Protestants, significantly fewer of them now approve of his performance in office (55% approve, 38% disapprove) than was true at the start of his second term when 72% approved and only 22% disapproved.

Indeed, since he began his second term in office, Bush's approval rating has declined as much among white evangelicals as among the public as a whole [...] 45% of evangelicals agreed with the statement that "I am tired of all the problems associated with the Bush administration" - less than a majority but a sizable number nonetheless.

Yet there is little indication, as of now, that evangelicals are likely to abandon the Republican Party electorally. Pew's polling finds that the percentage of white evangelicals identifying as Republicans has actually increased slightly in 2006, and the number of these who say they intend to vote for Republican candidates this November is no lower now than it was at a comparable point in 2002, the last mid-term election.

The Pew study offers some useful background on the role of white evangelicals in U.S. politics:

[W]hite evangelicals have become the bedrock of the GOP. In the 2004 election, they were the largest single demographic group among Bush voters, constituting fully 35% of his total. By comparison, African Americans - the most loyal of Democratic constituencies - constituted only about one-fifth (21%) of Kerry's voters.

The rising political clout of evangelical Christians is not the result of growth in their numbers but rather of their increasing cohesiveness as a key element of the Republican Party. The proportion of the population composed of white evangelicals has changed very little (19% in 1987; 22% now) and what growth there was occurred in the late 1980s and early 1990s.

The South was key to the transition: Southern white evangelicals stayed in the Democratic Party into the late 1980s, but by the close of the 1990s most had jumped ship.

White evangelicals seem determined to stay in the GOP camp. The Pew study shows that, more than any other group, they are sticking with their party:

[W]hite evangelicals remain committed to the GOP. In an April Pew poll, 64% of evangelicals said they intended to vote for the Republican candidate for Congress this fall, while 29% said they would vote Democratic (7% were undecided). (By comparison only 41% of all voters say they will opt for a Republican in Congress while 51% say they will pick a Democrat.)

Thus there is no sign that Bush's troubles are currently having a significant impact on the support of this key Republican constituency for the party's candidates this fall. Moreover, most evangelicals continue to give the party good marks for the job it's doing standing up for its traditional positions. Currently, 59% of Republican or Republican-leaning evangelicals say the party is doing either an excellent or good job in this respect. That is significantly higher than the 47% rating the party earns among all Republicans and GOP leaners.