I've long tried to understand the double-standard when it comes to politicians and sex scandals -- while common sense suggests they should be far more damaging to Republicans given the party's moralizing, the opposite appears to be true.

Dave Weigel takes a crack at explaining this, noting three, recent, high-profile adulterers: Eliot Spitzer (D-N.Y.), David Vitter (R-La.), and Mark Sanford (R-S.C.). The two Republicans ran as evangelical, "family-values" conservatives, but got caught having sex with women who were not their wives. (In Vitter's case, he was caught with at least two prostitutes.) Neither Republican resigned -- on the contrary, Vitter appears likely to win another term, and Sanford hasn't ruled out seeking public office again. Spitzer, meanwhile, resigned almost immediately after his sex scandal.