The story is told of the French diplomat in the bad days of the Cold War who was approached by a Soviet agent and shown pictures of himself having sex with a woman most definitely not his wife. This is called the “honey trap” and it is used by intelligence services to extort information by threat of blackmail. At any rate, our Frenchman nonchalantly put on his glasses and peered at the pictures. He pointed to one and then another. “I’ll take this one and that one and, yes, that one, too.”

The shocked KGB agent turned on his heels and left. A Frenchman cannot be blackmailed on account of sex.

Oddly enough, David Petraeus is now in the position of that Frenchman. His dalliance with his biographer, Paula Broadwell, is known to everyone on the planet, including yak herders in places I cannot spell. His personal computer’s hard drive has been ransacked by the FBI and possibly by his own CIA. Salacious tidbits have been leaked to us, the reading public, and we can only imagine what has been whispered in the corridors of the FBI. Another person’s sexual passion is always funny.

I have a glancing familiarity with Petraeus. I found him frank and personable — not at all what I expected. I have long maintained that a man of 60 who has no body fat is not to be trusted — but I found Petraeus to be the exception, a rebuff to Shakespeare’s Julius Caesar. (“Yond Cassius has a lean and hungry look; He thinks too much: such men are dangerous.”) Alas for Petraeus, he did not think enough. Such men are fools.

This thing with sex, this American obsession and its concurrent hypocrisy, has gone far enough. We went through a disgraceful attempt at a presidential coup with Bill Clinton, who was accused of lying about sex — imagine! — but survived to become a widely admired elder statesmen. We have seen members of Congress destroyed by personal peccadilloes that had nothing to do with their public responsibilities. Robert Livingston, R-La., was about to succeed Newt Gingrich as speaker of the House when an extramarital affair was discovered. He not only gave up the speakership but left the House and has spent his purgatory as a Washington lobbyist. (Livingston was succeeded by David Vitter, now a senator, who admitted being a client of the so-called D.C. Madam.)

The list of Washington sex scandals is long and, really, quite distinguished. One would have to include John F. Kennedy and, just to be fair, Thomas Jefferson. I want to mention Warren Harding, a randy devil he, and even Dwight D. Eisenhower, whose wartime affair with his driver, Capt. Kay Summersby, has long been alleged. Lyndon Johnson’s affairs have been documented by the indefatigable Robert Caro — and were all but conceded by the weary Lady Bird Johnson. These matters can hurt.

It may turn out that Petraeus’ greatest intelligence failure had nothing to do with what happened at Benghazi but with his utter disregard of the novelist Nelson Algren’s three rules of life: “Never play cards with a man called Doc. Never eat at a place called Mom’s. Never sleep with a woman whose troubles are worse than your own.”

Many a man, including Algren, who hooked up with the difficult Simone de Beauvoir, has disregarded these rules to his regret. Petraeus has to be added to this list. Broadwell was reckless with her emails and she then promoted her book with a bit more than wink: She was embedded with him. The book is called All In. Oh, grow up!

But now that it has all been done, is there a better man to fill Petraeus’ seat than Petraeus himself? He is blackmail-proof and more than qualified for the job. He not only was a four-star general, a West Point grad (top 5 percent of his class) and a Princeton scholar, but, in the quite recent past, he held the director’s job himself. The United States would not only be getting the best man for the job, but striking a blow against the sexual McCarthyism that has destroyed so many careers and, in wretched silence, has aborted many a political career before it was even announced.

At dinner one night, I sat opposite Holly Petraeus. She’s charming and deeply concerned about the welfare of our troops — both active and retired. I can only imagine her hurt. But this is her matter — and her husband’s — and not ours. He betrayed her, not his country. No more need be said. Now get back to work.