A total bombshell, breaking right now on Fox. Catherine Herridge says the only explanation given so far is “personal reasons,” but notes that he met personally with Obama yesterday and wonders if it may have had to do with the CIA releasing that timeline on Benghazi last week. That was my gut instinct too — either this is fallout from Benghazi or there really is something personal going on.

Judging from this tidbit, it’s at least partly personal:

CIA Director David Petraeus submits letter of resignation, cites extra-marital affair – @msnbc broadcast — Breaking News (@BreakingNews) November 9, 2012

Why would an affair mean that he couldn’t run the CIA anymore? Was he being blackmailed? Or is there more to it than this? Stand by for updates.

Update: His statement:

“Yesterday afternoon, I went to the White House and asked the President to be allowed, for personal reasons, to resign from my position as D/CIA,” Petraeus said in a statement to CIA staff. “After being married for over 37 years, I showed extremely poor judgment by engaging in an extramarital affair. Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours.”

If you’d have asked me to list 100 possible reasons why David Petraeus would eventually quit public service, having an affair would have been number 100. If it made the list at all.

Update: NBC says deputy CIA director Mike Morrell is likely to be named interim director, and may well end up being elevated to permanent status.

Update: As for the timing, I assume Petraeus intended to do this for awhile but held off until after the election so that it wouldn’t end up influencing the vote. The media spotlight on the campaign would have only drawn more attention to his predicament and magnified the embarrassment.

Which makes me wonder: If he did fear being blackmailed, why didn’t some potential blackmailer use the campaign as leverage, threatening to push this out there before the big vote if he didn’t pay up?

Update: I’m seriously shocked. The last thing I’d expect from him is a breakdown in personal discipline.

Update: For what it’s worth, Andrea Mitchell and MSNBC are hearing that Petraeus’s resignation really doesn’t have anything to do with Benghazi.

Update: I’m already getting e-mails speculating that the administration wanted him out over Benghazi and that they were the ones who forced his hand by threatening to expose his affair if he didn’t quit. I don’t follow the logic there. If that were true, the ultimatum would have been that he could either resign and keep the affair secret to avoid disgrace or have the affair exposed and then inevitably be pressured to resign anyway. Makes no sense for him to resign before the affair’s been revealed and then admit to it in his resignation.

Besides, would the White House really dare try to strongarm David Petraeus, of all people, that way? He’s probably the most widely esteemed member of Obama’s administration. If they used sleazy tactics to try to force him out, they’d live in mortal terror of him revealing the blackmail attempt and using it to turn the public against O. Just makes no sense to me.

Update: Reader “Flip” makes a nice catch. Petraeus’s resignation letter says, “After being married for over 37 years, I showed extremely poor judgment by engaging in an extramarital affair.” But Petraeus has actually been married for more than 38 years; the wedding was on July 6, 1974. In other words, if you read the resignation letter carefully, he’s telling you that this happened sometime between July 2011 and July 2012, not recently. Why didn’t he resign sooner? Or, on the flip side, why didn’t he try to hang on longer if he’d held on this long already?

Update: Hmmmmmmmm:

Senate Intelligence Committee says Petraeus will not testify at next week’s closed hearing on the events in Benghazi. — Mark Knoller (@markknoller) November 9, 2012

Again, though — if this was actually engineered by the administration to force him out, why wouldn’t Petraeus reveal that publicly? After all of his service, he deserves better than to be blackmailed, even if he’s guilty of a major lapse in judgment.

Update: Obama’s statement:

David Petraeus has provided extraordinary service to the United States for decades. By any measure, he was one of the outstanding General officers of his generation, helping our military adapt to new challenges, and leading our men and women in uniform through a remarkable period of service in Iraq and Afghanistan, where he helped our nation put those wars on a path to a responsible end. As Director of the Central Intelligence Agency, he has continued to serve with characteristic intellectual rigor, dedication, and patriotism. By any measure, through his lifetime of service David Petraeus has made our country safer and stronger. Today, I accepted his resignation as Director of the Central Intelligence Agency. I am completely confident that the CIA will continue to thrive and carry out its essential mission, and I have the utmost confidence in Acting Director Michael Morell and the men and women of the CIA who work every day to keep our nation safe. Going forward, my thoughts and prayers are with Dave and Holly Petraeus, who has done so much to help military families through her own work. I wish them the very best at this difficult time.

Update: Some of Petraeus’s former aides tell Danger Room they’re just as shocked as the rest of us.

Update: Now might be a good time to read (or re-read) the Journal’s story from eight days ago about the massive miscommunication between the CIA and State over who was supposed to be protecting the consulate in Benghazi. Title: “CIA Takes Heat for Role in Libya.”

Update: Note to Congress: Subpoena the general.

Resignation doesn’t give you a free pass out of testifying to Congress. They can subpoena him if they want, can’t they? — Josh Greenman (@joshgreenman) November 9, 2012

Update: Speaking of Benghazi-related political clusterfarks, word on the street is that John Kerry might be passed over as the next Secretary of State in favor of — ta da — Susan Rice, the face of the White House’s initial nonsense about the attack. (GOP senators are already warning O to think again.) Rice’s now infamous appearance on the Sunday shows was actually informed by early CIA “talking points,” so there’s another reason to think that the agency’s performance might have somehow influenced Petraeus’s departure today.

Update: Annnnd the hits just keep on coming. There’s no stopping this Friday-news-dump train!

Update: A parting thought, for now: If the affair didn’t happen recently, why didn’t he hold off on revealing it and resigning for another week, until after he was done testifying to Congress about Benghazi?

Update: Fred Kaplan, Slate’s plugged-in military reporter, says he knows who Petraeus had an affair with. The photo of the book cover at the top of Drudge right now has more meaning than you think.

Update: Oh boy. Starting to become clear why this affair required a resignation:

FBI investigating Petraeus biographer Paula Broadwell for improperly trying to access his email, officials tell @nbcnews — Breaking News (@BreakingNews) November 9, 2012

Update: Note the author and the date. And rule number five.

Update: Here’s a fun contest for readers. Try to reconcile these two statements. Statement one:

The biographer for resigning CIA Director David Petraeus is under FBI investigation for improperly trying to access his email and possibly gaining access to classified information, law enforcement officials told NBC News on Friday.

Statement two:

The law enforcement officials said they do not believe the FBI investigation will result in any criminal charges.

“Improperly” trying to read the DCIA’s e-mail isn’t a federal offense?