I believe there is value in allowing the government to be able to get at metadata not because it holds it and stores it itself but because it’s gone through the normal legal process to contribute information to actual and prospective threats. So for 702 the record is unambiguous. For section 215 [of the Patriot Act] it doesn’t have the overwhelming character of the 702 program in terms of effectiveness.

JR: Section 215 of the Patriot Act has been the most controversial provision, especially as construed by the FISA Court, which would allow the government to seize any data that might be relevant to future investigations that don’t yet exist. How would your report change the construction of section 215?

CS: Probably most important thing in the report on section 215 is that the metadata material shouldn’t be held by the government any more. Many people are concerned that the government is holding and storing telephone metadata, and we share that concern. It’s not that government has been prying into people’s private life and going after dissenters. But there are risks if the government holds this material. There are risks to public trust, to privacy and liberty. We think that a better system is one in which private providers hold that information and the government can’t get access to it except by getting judicial authorization. The judicial authorization would be available on two conditions. First, the request has to be reasonable and focused in scope and breadth. You can’t get subpoena by saying I want everyone’s phone calls. Second, the government has to have not just a wish for material but reasonable grounds to believe that material its seeks is relevant to an investigation to protect against international terrorism or clandestine terrorist activity.

If after the bombing in say, Boston, the government has reasonable grounds to figure out who was having conversations with a suspect, there’s a pretty good argument that the information sought is relevant and time may be of the essence. The idea of getting who is calling whom, that’s legitimate under standard legal rules, but the idea is that government isn’t holding material and the court will allow the government to have access only on a particular showing.

JR: So if your recommendations are adopted, the government couldn’t do the “three hops” analysis it’s doing now, where it investigates all the numbers called by a suspect, all the numbers those numbers call, and all the numbers those numbers call?

CS: No, not unless you specified what you wanted. Three hops would be a lot to ask for, and you’d’ have to explain why that is a good idea. Obviously, in the aftermath of an apparent terrorist attack either of the magnitude of what happened after 9/11 or the magnitude of what happened in Boston, our report didn’t specify what would be the acceptable requests. But if you had a terrible attack, the government might reasonably want more than it would if it just had a report of a possibility.

JR: Your group didn’t have access to Judge Richard Leon’s opinion questioning the constitutionality of the metadata surveillance program. But it’s consistent with some of your recommendations.

CS: I didn’t read the opinion after the report was finalized and I haven’t gone back and forth from one document to the other. Our report is free standing. The members of our group have a legal background, but we weren’t making a legal determination. Our task was to think about policy.

JR: How would shutting down the database work in practical terms?

CS: The idea would be that phone companies already have the information and voluntarily some of them hold the information for a long time. They would have it, and the government could get access if it needed it. The challenge for the government is what if the phone calls involve several carriers? Can they figure out this carrier was involved and this one and can they query them in away that is workable despite the fact that there talking to different entities? We believe that is technically feasible. The idea would be that government would go to carriers with a technical mechanism by which it could check the various numbers that are involved. We recognize that our judgment that this is technically feasible is an empirical judgment and not every one shares it. We suggest that if it turns out not to be feasible, an alternative worth considering would be another private entity that could hold the material. It would have to be a genuinely private entity. We would leave to others which that private entity should be. That's not our preferred outcome, though. Our preferred outcome is that there’s a need to access the material, and you get to the people who have the metadata.

JR: So the current data collection system and the government database would have to be shut down?

CS: Yes, we would transition from a system where the government has the information to one, which is based on the status quo, where phone companies have the information.

JR: if you could pick a single recommendation to be implemented, what’s the most important?

CS: I wouldn’t single out any one. We’re committed to all 46.