The Problem With FISA

Judge Richard Posner pins it down:

So the problem with FISA is that the surveillance it authorizes is unusable to discover who is a terrorist, as distinct from eavesdropping on known terrorists--yet the former is the more urgent task. Even to conduct FISA-compliant surveillance of non-U.S. persons, you have to know beforehand whether they are agents of a terrorist group, when what you really want to know is who those agents are.

FISA's limitations are borrowed from law enforcement. When crimes are committed, there are usually suspects, and electronic surveillance can be used to nail them. In counterterrorist intelligence, you don't know whom to suspect–you need surveillance to find out. The recent leaks from within the FBI, expressing skepticism about the NSA program, reflect the FBI's continuing inability to internalize intelligence values. Criminal investigations are narrowly focused and usually fruitful. Intelligence is a search for the needle in the haystack. FBI agents don't like being asked to chase down clues gleaned from the NSA's interceptions, because 99 out of 100 (maybe even a higher percentage) turn out to lead nowhere. The agents think there are better uses of their time. Maybe so. But maybe we simply don't have enough intelligence officers working on domestic threats.

(via Instapundit)