Amazing … that there are that many of us voting Republican, that is. Didn’t we see some numbers in this vein not long ago pointing towards a more lopsided outcome?

The atheist vote’s just a sexy detail in an omnibus poll of religious voters. The good news: Obama’s lost seven points among Christians since June and has seen his support soften considerably in several subgroups. The bad news: Pretty much everything else, especially the fact that McCain’s only gained one point in the same period and trails among every “faith segment” except one. If Obama has a “Catholic problem,” what do we call McCain’s predicament? A “Catholic crisis”?

For the most part, the various faith communities of the U.S. currently support Sen. Obama for the presidency. Among the 19 faith segments that The Barna Group tracks, evangelicals were the only segment to throw its support to Sen. McCain. Among the larger faith niches to support Sen. Obama are non-evangelical born again Christians (43% to 31%); notional Christians (44% to 28%); people aligned with faiths other than Christianity (56% to 24%); atheists and agnostics (55% to 17%); Catholics (39% vs. 29%); and Protestants (43% to 34%). In fact, if the current preferences stand pat, this would mark the first time in more than two decades that the born again vote has swung toward the Democratic candidate.

However, while there has been little movement since the beginning of June among most voting segments (such as ethnic groups, age groups, or geographic slices), there has been substantial churn among religious segments. During the past two months, Sen. Obama’s lead has eroded substantially among non-evangelical born again Christians (a decline of nine points); active Christians (a 20-point drop); Protestants (down 13 points); and Catholics (down 11 points).

Even McCain’s lead among evangelicals comes with an asterisk: It’s based on Barna’s (more precise) definition of what counts as “evangelical,” not whether people describe themselves that way. By the latter definition, he’s ahead only 39/37. And even by Barna’s definition, he’s lost 17 points since June. I have no explanation for that except possibly his decision to cut Hagee and Parsley loose. That came on May 22; maybe the news didn’t penetrate among evangelicals for a few weeks. It can’t be that Obama’s evangelical outreach program is peeling tons of people away or else the margin between them would be closer.

All in all, no surprise given how many Americans are Christian that the same recent trends in national polls show up here — lots of people still undecided and Obama’s halo starting to dim a bit, with McCain unable to capitalize. I read something the other day speculating that he has a ceiling of about 45 percent; I’m starting to worry that that may be true. Exit question: Can you name one high-profile evangelical who’s stumping hard on his behalf? Huckabee was the obvious choice to be a liaison to Christians but aside from a few token joint appearances I haven’t heard of him doing much of anything. McCain’s own credentials are sufficiently suspect among this constituency that you’d think the campaign would be clamoring for credible surrogates to get out on the trail for him, but … nothing. What gives?