Noting the comeback campaigns of Eliot Spitzer and Anthony Weiner in New York, feminist author Hanna Rosin wonders why “50 years into the sexual revolution” women politicians lag so far behind men in the sex-scandal tally. She notes biological and evolutionary explanations only to reject them in favor of the idea that women are just too unused to power to abuse it in that way. She’s cheered, though, by surveys showing that younger women are cheating on their spouses almost as much as men, and confidently looks forward to the not-too-distant day when we’ll “find ourselves willing to look past...