Amazingly, many members of Congress talk as if the real outrage here was that they weren’t informed earlier about the investigations of Petraeus and Allen. “We should have been told,” said Dianne Feinstein, chairman of the Senate intelligence committee, last Sunday. To which an observer might respond vernacularly: Give me a break.

The idea seems to have developed that the CIA and the military work equally for Congress and for the executive branch. They don’t. They work for the president, who is commander in chief. Congress appropriates the money and has a legitimate role in overseeing how it’s spent. But the idea that these scandals demonstrate the need for greater congressional involvement in sensitive investigations is preposterous.

The day Petraeus resigned, I received an e-mail from an Arab intelligence contact who expressed what surely has been going through the minds of many people around the world. I will quote it precisely, punctuation and all: “He needs to resign cause he has an affair? What da hell??? He is brilliant!!!! Why like this????”

Petraeus is gone, but the hunt for miscreants is still gathering force. For a reminder of why it’s dangerous, take a look at “The Crucible” and the lessons of history.