The number of people who would be cleared to possess the level of detail that identified a particular conference call as the relevant SIGINT actiity is tiny. It is one thing to say broadly that U.S. officials overheard “discussions,” because someone planning an attack probably discusses it in some way many times. Even then, though, you could imagine a mad scramble by jihadists for new communication safe zones.

There are two reasons why the government would tolerate this type of leak. One: the threat was so severe that the only way to prevent it was to expose the plot completely, showing Al Qaeda that the U.S. had penetrated so deeply into their organization that the big boss’s double-top-secret conference call was recorded. It’s the counter-terrorism equivalent of face up poker. There’s an element of brinksmanship in this approach.

Two: the U.S. intelligence community might want Al Qaeda to shift its communication methods because the new method Al Qaeda ends up with might be more intercept friendly in the future, or the U.S. believes that certain Al Qaeda members it keeps under constant surveillance will help them quickly figure out the new method.