Judge Richard Posner argues that our laws about how to protect our security through gathering intelligence still have gaps in them and that we should address those weaknesses in our system. There is an interesting debate to be had here.

The Foreign Intelligence Surveillance Act makes it difficult to conduct surveillance of U.S. citizens and lawful permanent residents unless they are suspected of being involved in terrorist or other hostile activities. That is too restrictive. Innocent people, such as unwitting neighbors of terrorists, may, without knowing it, have valuable counterterrorist information. Collecting such information is of a piece with data-mining projects such as Able Danger.

The goal of national security intelligence is to prevent a terrorist attack, not just punish the attacker after it occurs, and the information that enables the detection of an impending attack may be scattered around the world in tiny bits. A much wider, finer-meshed net must be cast than when investigating a specific crime. Many of the relevant bits may be in the e-mails, phone conversations or banking records of U.S. citizens, some innocent, some not so innocent. The government is entitled to those data, but just for the limited purpose of protecting national security.

The Pentagon's rush to fill gaps in domestic intelligence reflects the disarray in this vital yet neglected area of national security. The principal domestic intelligence agency is the FBI, but it is primarily a criminal investigation agency that has been struggling, so far with limited success, to transform itself. It is having trouble keeping its eye on the ball; an FBI official is quoted as having told the Senate that environmental and animal rights militants pose the biggest terrorist threats in the United States. If only that were so.

The debate we've been having about the Patriot Act doesn't seem to be that debate.

If legislators are so upset about the warrantless eavesdropping by the NSA on people in the US communicating with Al Qaeda overseas, they can pass a law clarifying the matter. If the President thinks that he has the power in the Constitution, he can veto it. Let the debate begin.