Powerful man, beguiling woman: The combination has been sabotaging national interests since the days of Troy. Should David Petraeus’ affair with groupie-biographer Paula Broadwell have forced his resignation? Sadly, yes.

It’s not a matter of Puritanism, which – take note, sophisticates – hardly saturates American culture these days. Although betrayal of marriage vows and a wife of 37 years reflects poorly on Petraeus as a husband, it’s the least of the reasons this distinguished soldier had to step down as the nation’s chief intelligence officer.

Far more important is the fundamental lack of judgment and caution Petraeus displayed in getting himself entangled with Broadwell. As a West Point graduate, Reserve lieutenant colonel and all-around American superwoman, she hardly seems a treacherous Bond girl. Still, Petraeus let his guard down, an inexcusable lapse in a CIA chief.

He potentially exposed himself to blackmail, and he opened a clandestine door into his affairs that might have been exploited. An intelligence official bent on carrying on outside his marriage should at least keep a few alert colleagues in the loop.

It’s a shame that this scandal will always dog America’s memories of Petraeus, just as the Monica Lewinsky affair will always dog Bill Clinton. Leaders shouldn’t be defined by the dumbest thing they ever did. But when it’s dumb enough to be unforgettable, its place in history is assured.