Posner proposes a set of firewalls with criminal penalties and post intercept review in today’s WSJ:

It is a mistake to think that the only way to prevent abuses of a surveillance program is by requiring warrants. Congress could enact a statute that would subject warrantless electronic surveillance to tight oversight and specific legal controls, as follows:

1. Oversight: The new statute would —

(a) Create a steering committee for national security electronic surveillance composed of the attorney general, the director of national intelligence, the secretary of homeland security (chairman), and a senior or retired federal judge or justice appointed by the chief justice of the United States. The committee would monitor all such surveillance to assure compliance with the Constitution and laws.

(b) Require the NSA to submit to the FISA court, every six months, a list of the names and other identifying information of all persons whose communications had been intercepted without a warrant in the previous six months, with a brief statement of why these individuals had been targeted. If the court concluded that an interception had been inappropriate, it would so report to the steering committee and the congressional intelligence committees.

2. Specific controls: The statute would —

(a) Authorize “national security electronic surveillance” outside FISA’s existing framework, provided that Congress declared a national emergency and the president certified that such surveillance was necessary in the national interest. Warrants would continue to be required for all physical searches and for all electronic surveillance for which FISA’s existing probable-cause requirement could be satisfied.

(b) Define “national security” narrowly, excluding “ecoterrorism,” animal-rights terrorism, and other forms of political violence that, though criminal and deplorable, do not endanger the nation.

(c) Sunset after five years, or sooner if the declaration of national emergency was rescinded.

(d) Forbid any use of intercepted information for any purpose other than “national security” as defined in the statute (point b above). Thus the information could not be used as evidence or leads in a prosecution for ordinary crime. There would be heavy criminal penalties for violating this provision, to allay concern that “wild talk” picked up by electronic surveillance would lead to criminal investigations unrelated to national security.

(e) Require responsible officials to certify to the FISA court annually that there had been no violations of the statute during the preceding year. False certification would be punishable as perjury.

(f) Bar lawsuits challenging the legality of the NSA’s current warrantless surveillance program. Such lawsuits would distract officials from their important duties, to no purpose given the new statute.

Destroying the negative data would be the only thing I would add to assure that Posner’s robot searchers don’t tell their tales to humans. I would subtract the barring of lawsuits. We need some catharsis. I would also subtract the Congressional declaration. Why should we expect the targets to give us any notice that they are on the war path?