Newt Gingrich has been on a tear, boosted, some of us have argued, by unexpected support from Christian conservatives.But the new GOP frontrunner and Catholic convert may have stumbled in an interview with ABC's Jake Tapper, broadcast this morning, in which he argued that life begins at successful implantation of a fertilized egg in the uterine wall, not at fertilization, as the Catholic Church now teaches:

TAPPER: Abortion is a big issue here in Iowa among conservative Republican voters and Rick Santorum has said you are inconsistent. The big argument here is that you have supported in the past embryonic stem cell research and you made a comment about how these fertilized eggs, these embryos are not yet "pre-human" because they have not been implanted. This has upset conservatives in this state who worry you don't see these fertilized eggs as human life. When do you think human life begins?GINGRICH: Well, I think the question of being implanted is a very big question. My friends who have ideological positions that sound good don't then follow through the logic of: So how many additional potential lives are they talking about? What are they going to do as a practical matter to make this real?'I think that if you take a position when a woman has fertilized egg and that's been successfully implanted that now you're dealing with life. because otherwise you're going to open up an extraordinary range of very difficult questions.

Yes, that does open up a range of difficult questions, and they are questions that another former House speaker and practicing Catholic, Nancy Pelosi, stumbled over back in 2008 -- prompting a wave of criticism and scorn from conservative Catholics, as Bob Imbelli noted in a post at the time at dotCommonweal.Maybe Pelosi's lapse wasn't as "teachable a moment" as we hoped. Will we hear catcalls for Gingrich on this one as well?Perhaps. Over at CatholicVote.org, conservative activist Joshua Mercer is not amused. "An unforced error," he calls it.

"Newt Gingrichs answer on when human life begins is simply unacceptable.But his mistake isnt due to timidness like when Pawlenty pulls his punchor from a profoundlack of debate skills like Perrys oops moment. No, Newt Gingrichs error is much worse because he actually believes something which is wrong. Andit hasdrastic consequences."

Interestingly, Newt aced Catholic Vote's Thanksgiving straw poll of more than 13,000 online ballots, with an impressive 44 percent take -- far more than even uber-Catholic Rick Santorum's second-place finish at 14 percent, and perhaps an early indicator of his current surge.Could "oops" moments like this drain that religious support?Or can Newt row it back? or maybe he'll say it's just "a conscience thing"?Cross-posted at S&P