The first Washington sex scandal I remember following involved Daniel Crane, a Republican congressman from my home state of Illinois, who was censured in the (first) House page scandal in 1983.

In July of that year, the House Ethics Committee announced that Crane and his Democratic colleague Gerry Studds (Mass.) had been accused of having sex with teenagers in the congressional page program — Crane with a young woman who was 17, and Studds with a young man the same age. The committee originally voted to reprimand both men, but a little-known congressman from Georgia argued that a mere reprimand wasn’t punishment enough.

Yes, it was Newt Gingrich who pushed for their expulsion — and as a result, the matter was put to a vote of the full House, where Crane and Studds became the first members ever censured over allegations of sexual misconduct.

Crane, a married father of six, tearfully confessed that the allegations were true. Oh, not good, I ventured to my staunchly Republican and seriously Catholic dad, who I knew had broken off friendships with guys who, as he put it, “liked to cat around.”

His response surprised me: Obviously, poor Crane was the victim, having been entrapped or libeled by the liberal media. Because, he said, it’s Democrats who have no morals. (As it happened, Crane was tossed out of office by voters in his conservative district, while Studds was spared in his more liberal one. See?)

Three decades later, I am unamazed that Republican primary voters are willing to look past the three wives and lively past of the former House speaker, particularly after a TV newsguy went after him right in front of Jesus and the American public. The only better scenario for Gingrich than having CNN’s John King ask him about his alleged “open marriage” request to his second wife, Marianne, would have been if King had asked a follow-up question twice as sassy.

The debate audience’s standing ovation after Gingrich blasted King for raising the issue helped propel the Georgian to victory in the South Carolina primary. But does Republican voters’ apparent nonchalance about Gingrich’s past mean that infidelity is the new divorce? That is, just as voters eventually accepted divorced political aspirants, are we now so inured to indiscretion that we can forgive a candidate’s moral lapses and still cite family values as a reason for supporting him?

Not exactly. The penalty for such transgressions depends on timing, how much voters liked the guy before and what the other options are. How such private issues are made public also matters, though partisans across the spectrum almost always see reporters as overzealous in going after sexual misbehavior, even if most of us run from such assignments.

In the case of former GOP candidate Herman Cain, allegations of sexual harassment and an affair seemed to get traction only in tandem with his lengthening string of foreign policy flubs. (This month, he told a crowd at the Stephen Colbert rally in Charleston, S.C., that it was, yes, the media that had driven him from the race, because he was too big a threat to the status quo.)

I’ve seen no politician more reviled over an affair than former senator John Edwards (N.C.), partly because of the public’s fondness for his wife, Elizabeth, but most heatedly by Democratic donors who wanted their money back. In that case, the news media caught hell for not pursuing the rumors sooner — though if Edwards had been in the remotest danger of nabbing his party’s 2008 presidential nomination, that would have changed faster than you could ask, “What were you thinking?”

On both right and left, reporters’ questions about sex reliably provoke at least as much sympathy as outrage. And on both right and left, a common reaction to such reports is a charge of hypocrisy. (Republican: You people thought this wasn’t a problem when it was Bill Clinton! Democrat: You wanted Bill Clinton drawn and quartered, and now it’s fine?)

Ask a Republican about Gingrich’s history of philandering, and the odds are excellent that the next sentence you hear will include the words “Bill Clinton.” (Which does seem a snub to Edwards, Anthony Weiner, Eliot Spitzer, David Paterson and more.) The morning after the South Carolina debate at which Gingrich went after King, Charlestonian Anne Atwater King — no relation to the moderator, but sister of the late strategist Lee Atwater — told me she was indignant that Gingrich had been asked such a tacky question. “How can the Democrats say anything about Newt Gingrich,” she said, “when Bill Clinton. . .” She neither finished the sentence nor had to.

Matter of fact, mention Gingrich to a non-Republican, and you are also quite likely to hear about Clinton: “At least Bill Clinton never brought any of his mistresses back to Hillary’s bed,’’ volunteered a Democrat named Cookie Washington at the Colbert rally later that day.

“At least Bill Clinton had the survival instincts not to ask” for an open marriage, wrote blogger Taylor Marsh.

“At least he never tried to drape his genitals in the flag,’’ wrote Slate’s Emily Yoffe, referring to Gingrich’s contention that it was passion for America that had sometimes led him astray.

This past week in Miami, campaigning ahead of the Florida primary next Tuesday, Gingrich angrily rejected the comparison: “I didn’t do the same thing” as Clinton, he insisted. “I never lied under oath, I have never committed perjury, I have never been involved in a felony.” And unlike Clinton when asked about Monica Lewinsky, he said, he told the truth when deposed under oath in his divorces.

When Univision’s Jorge Ramos tried again, Gingrich questioned his ability to process information: “There is someplace there where there’s a mental synapse missing.”

But how the public processes such nuances depends most of all, as has always been the case, on the affiliation of the politician being accused.

Melinda Henneberger is a Washington Post political writer and anchor of the blog “She the People.” Follow her on Twitter at @MelindaDC.