The sudden resignation of CIA Director David Petraeus on Friday was - as Sen. Diane Feinstein noted - like "a lightning bolt" hit Washington.

According to reports, the retired general offered his resignation to President Barack Obama on Wednesday afternoon and the president officially accepted it Friday.

The CIA director offered to resign after it was confirmed he had an affair with former staffer and biographer Paula Broadwell. The affair was discovered after the FBI investigated threatening emails Broadwell sent to another woman.

Congressional investigations to see if there was a threat to national security are sure to follow.

The revelations are shocking and heartbreaking for a number of reasons. First of all, of course, Petraeus was a heroic figure in the Army. His planning and execution of the "surge" in Iraq are credited with turning the tide in the war there.

His personal valor and conduct built up an inner circle of officers that admired and advised him.

A second, and lesser known, reason that this is such a tragedy is that Petraeus' wife of 38 years, Holly, is a well-known advocate for military families. She not only fought for them under her husband's various commands, but she has been a force on the Hill constantly reminding Congress to take care of soldiers' families.

It is an ignominious end to Petraeus' public career. It is also a loss not just for his family, but for the country.

* Editorials reflect the opinion of the publisher.