From the Washington Post tonight:

 The collapse of the impressive career of CIA Director David H. Petraeus was triggered when a woman with whom he was having an affair sent threatening e-mails to another woman close to him, according to three senior law enforcement officials with know­ledge of the episode.

The recipient of the e-mails was so frightened that she went to the FBI for protection and help tracking down the sender, according to the officials. The FBI investigation traced the threats to Paula Broadwell, a former military officer and a Petraeus biographer, and uncovered explicit e-mails between Broadwell and Petraeus, the officials said.

When Petraeus’s name surfaced, FBI investigators were concerned that the CIA director’s personal e-mail account had been hacked and that national security had been threatened.

But no, it was just the head of the CIA extramaritally screwing a nut who sent threatening e-mails to a woman she perceived as a sexual rival for the affections of the CIA director. Who was having an extramarital affair.

What if this Broadwell woman had been in the pay of the Russians, or the Chinese? Petraeus isn’t the first powerful man to behave immorally and dishonorably with regard to betraying his marital vows, and he won’t be the last. That’s between him and Mrs. Petraeus. The thing that is the most shocking and appalling about this is the potential national security threat his affair posed to the  country. You think Petraeus’s affair is news to the Russians? The recklessness of Petraeus’s behavior is profoundly scandalous. Hasn’t he seen the movie?

UPDATE: The WaPo is all over this story. The paper’s Max Fisher writes, about an unauthorized photo Broadwell posted to her Facebook wall of a photo taken of Petraeus and Angelina Jolie in his CIA office, which is photographically off-limits to all but the CIA’s official photographer:

Posting a photo of Petraeus with a movie star on a Facebook page is obviously not much of a national security breach. But what may have raised concern is the pair’s apparent disregard, at least in this incident, for following security procedures and for circumspection. If she was posting unapproved photos of the CIA director’s office on her Facebook wall, then, you have to wonder, what did she see as too sensitive for social media but fine to share with friends? Or what did Petraeus feel was appropriate to share with her privately?

The point is not that Broadwell had access to anything more sensitive than a forbidden photo of her secret lover’s office, or that Petraeus had to share anything more. The point is that they, based on the reports out so far, disregarded normal CIA security procedures — which would also require disclosing a secret affair, given the potential for blackmail — and appeared to have invented their own. That Petraeus would invite someone into his personal and professional world — especially someone who was well known for being temperamental — without regard for normal security standards would be no small breach.