First: Absolution does not perfect character, and even a sincere penitent may have demonstrated, by his past behavior, characteristic weaknesses that could lead to a repetition of the offense. Gingrich has said that his adultery resulted, at least in part, from getting so caught up in his work for the American people as speaker. If that is true, then high office would seem to be an occasion of sin that Americans have a reason of charity to spare him. (If there are stronger reasons on the other side of the case — for example, we think that he’s really the only person who can save the country — they could defeat this charitable obligation.)

Second: Catholic teaching and practice wisely seek to avoid “scandal,” which in this context might be best understood as actions that inadvertently spread moral misunderstanding. Making a known adulterer president might run the risk of teaching the false lesson that adultery (or immorality generally) is not important. Considerations of scandal lay behind the old Catholic practice of avoiding large weddings or Masses in the case of marriages after annulments. The Church was not trying to convey the view that the new marriages were somehow not real marriages. Nor was it saying that, in cases where the marrying parties had begun their relationship under sinful circumstances, the repentance of those sins was insincere, untrustworthy, or worth only partial credit. The point was to maintain, as much as possible, the public’s (or at least the Catholic public’s) understanding of Church teaching about marriage. So (in principle!) here. All else equal, a president with no history of adultery would be preferable.

Third: A primary voter might reasonably vote for another candidate on the grounds that a candidate known to have had extramarital affairs would have a harder time winning the general election.