NBC News reports:

CIA Director David Petraeus resigned Friday, citing an extramarital affair and "extremely poor judgment."

As first reported by NBC News and in a letter released to the CIA work force on Friday afternoon, Petraeus disclosed the affair, and wrote: "Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours."

Petraeus told President Obama of his affair and offered his resignation during a meeting on Thursday, a senior official told NBC News. In a phone on Friday, Obama accepted the resignation.

Let it be said: If you are the head superspy of the United States, and you can't even keep your own affair a secret, you probably should resign.