The conventional wisdom about McCain's narrow 3% win in South Carolina is that Fred Thompson ate into Huckabee's evangelical base, thus delivering the state to his buddy McCain.

From First Read:

Huckabee friendly counties were still out there, but Fred looks like the best thing he could have done for his friend John McCain was to keep in this race. In the past few days, we noticed the fervor of Fred heads in the Upstate and they came out for their candidate. He's pulling in 20+% of the vote there, and has clearly hurt Huckabee's margins. McCain, on the flip side, has wide margins in the Low Country. In Charleston, for example, 44-16, is McCain's lead... Huckabee isn't close to those margins

Delving into the exit polls reveals a couple flaws in this analysis. First of all, it overestimates Thompson's appeal among evangelical voters. Thompson got 16% of the total vote but only won 15% of the evangelical vote. In fact, he did slightly better (16%) among non-evangelicals. Thompson has no more appeal among conservative Christians than he does among the electorate as a whole.

It also underestimates John McCain's appeal among this key voting bloc. According to the exit polls, 60% of the GOP primary electorate identified themselves as "born again or evangelical Christian," of which Huckabee won 43%, McCain won 27%, Thompson won 15% and Romney 11%. If you take Thompson's share of the evangelical vote and distribute it among Huckabee, McCain and Romney in the same ratios in which those voters originally supported those three candidates (appx. 4:3:1), Mike Huckabee would have only gained between 1-2% over McCain, not enough for him to win outright.

Was Thompson a factor in Huckabee's loss? Sure, to the extent that he represented yet another candidate to vote for other than Huckabee, but Huck's real problem was that so many decided not to vote for him. In Iowa, which had a similar 60-40 split between evangelicals and non-evangelicals, Huckabee won 46% of that vote. If he had replicated that in SC, and taken the lion's share of those voters from McCain, that would have been enough to make up his 3% deficit to defeat McCain. So what went wrong for Huckabee in South Carolina?

Yesterday, I was watching some of CNN's Ballot Bowl and heard a telling comment from one of their correspondents covering South Carolina: that Mike Huckabee's comments about changing the constitution to conform to "God's standards" (Think Progress has the video) really made a lot of evangelicals uncomfortable.

Huckabee's statement:

"That's what we need to do, is to amend the constitution so that it's in God's standards rather than try to change God's standards so it lines up with some contemporary view of how we treat each other and how we treat the family," he told one group.

So, in other words, even evangelicals think he's batshit crazy. And so apparently do the denizens of the Free Republic, as do GOP voters all over by the look of some recent polling. Huckabee made the statements on January 15th, the same day as the Michigan primary, so it's difficult to conclude with certainty whether his loss there (and subsequent loss in SC) is responsible for his falling poll numbers or if it can be attributed to his statements about the constitution (perhaps it was a combination) but a look at his Rasmussen Reports daily tracking numbers (down 8% since the 15th, a fall from 1st to 3rd) and his falling Florida numbers (a 6% drop in the Insider Advantage Florida poll alone since his statement) it's hard not to come to the conclusion that Huckabee is done and I suspect his ill-advised comments will go down as the turning point. A key question moving forward is whether Romney, who's now remade himself into the turnaround artist, can pick up this key voting bloc as they begin to peel away from Huckabee.