Ross Douthat pointedly warns Christians to be very, very careful about associating themselves with Newt Gingrich — and for a good reason I’ve heard nobody else bring up. He points out that conservative Christianity is facing a big demographic challenge in this country. Younger American Christians are much less engaged by the same culture-war fights that have preoccupied their parents’ generation of Christians. As Robert Putnam and others have documented in social science research, many of the Millenials have turned from Christianity itself, or from conservative Christianity, out of dissent from the “Republican Party At Prayer” model of Christianity they discern there. Gingrich is a classic example the kind of thing that younger Christians (and ex-Christians) find so objectionable about the Religious Right, Ross points out, in that he is an icon of partisan piety that looks an awful lot like rank hypocrisy.

But wait, hasn’t Newt confessed Jesus and been forgiven of his sins? Perhaps so — but as Ross insists, that is beside the point:

But repentance isn’t the issue here. Of course Christians are obliged to forgive a penitent, whatever his offenses — though a cynic might note that it’s easy for an adulterer to express contrition once he’s safely married to his mistress. But one can forgive a sinner without necessarily deciding that he should be anointed as the standard bearer for the very cause that he betrayed. Contrition is supposed to be its own reward. There’s no obligation to throw in the presidency as well.

In a climate of culture war, any spokesman for conservative Christianity is destined to be a polarizing figure. (Just ask Tim Tebow.) But a religious right that rallied around Gingrich would be putting the worst possible face on its cause and at the worst possible time.

His candidacy isn’t a test of religious conservatives’ willingness to be good, forgiving Christians. It’s a test of their ability to see their cause through outsiders’ eyes, and to recognize what anointing a thrice-married adulterer as the champion of “family values” would say to the skeptical, the unconverted and above all to the young.

Absolutely right. Yet to that one might say: well, St. Paul was a persecutor of Christians, and look what he became. Okay, but is Newt St. Paul? St. Paul’s conversion, and later life, did not serve for his worldly glorification and entree to power. In fact, it landed him in prison, put his life in jeopardy, and, according to tradition, ultimately led to his martyrdom. Newt’s conversion has not borne similar fruits. Caveat emptor.