Leave it to Senator (!) Al Franken to remind DOJ officials of the Fourth Amendment in discussing the FISA (Foreign Intelligence Surveillance Act) Amendments upholding warrantless "roving" wiretapping. A roving wiretap is a wiretap specific to the United States that follows the surveillance target. The Patriot Act greatly expanded roving wiretapping.
Here is an excerpt from a great article from Cato @ Liberty that details the difference between roving wiretaps, Title III wiretaps, and the Fourth Amendment. Or as appellate Judge Sydney Thomas asked: "What happened to the Fourth Amendment? Was it repealed somehow?"
To understand the reasons for potential concern, we need to take a little detour into the differences between electronic surveillance warrants under Title III and FISA. The Fourth Amendment imposes two big requirements on criminal warrants: “probable cause” and “particularity”. That is, you need evidence that the surveillance you’re proposing has some connection to criminal activity, and you have to “particularly [describe] the place to be searched and the persons or things to be seized.” For an ordinary non-roving wiretap, that means you show a judge the “nexus” between evidence of a crime and a particular “place” (a phone line, an e-mail address, or a physical location you want to bug). You will often have a named target, but you don’t need one: If you have good evidence gang members are meeting in some location or routinely using a specific payphone to plan their crimes, you can get a warrant to bug it without necessarily knowing the names of the individuals who are going to show up. On the other hand, though, you do always need that criminal nexus: No bugging Tony Soprano’s AA meeting unless you have some reason to think he’s discussing his mob activity there. Since places and communications facilities may be used for both criminal and innocent persons, the officer monitoring the facility is only supposed to record what’s pertinent to the investigation.
When the tap goes roving, things obviously have to work a bit differently. For roving taps, the warrant shows a nexus between the suspected crime and an identified target. Then, as surveillance gets underway, the eavesdroppers can go up on a line once they’ve got a reasonable belief that the target is “proximate” to a location or communications facility. It stretches that “particularity” requirement a bit, to be sure, but the courts have thus far apparently considered it within bounds. It may help that they’re not used with great frequency: Eleven were issued last year, all to state-level investigators, for narcotics and racketeering investigations.
Surveillance law, however, is not plug-and-play. Importing a power from the Title III context into FISA is a little like dropping an unfamiliar organism into a new environment—the consequences are unpredictable, and may well be dramatic. The biggest relevant difference is that with FISA warrants, there’s always a “target”, and the “probable cause” showing is not of criminal activity, but of a connection between that target and a “foreign power,” which includes terror groups like Al Qaeda. However, for a variety of reasons, both regular and roving FISA warrants are allowed to provide only a description of the target, rather than the target’s identity. Perhaps just as important, FISA has a broader definition of the “person” to be specified as a “target” than Title III. For the purposes of criminal wiretaps, a “person” means any “individual, partnership, association, joint stock company, trust, or corporation.” The FISA definition of “person” includes all of those, but may also be any “group, entity, …or foreign power.” Some, then, worry that roving authority could be used to secure “John Doe” warrants that don’t specify a particular location, phone line, or Internet account—yet don’t sufficiently identify a particular target either. Congress took some steps to attempt to address such concerns when they reauthorized Section 206 back in 2005, and other legislators have proposed further changes—which I’ll get to in a minute. But we actually need to understand a few more things about the peculiarities of FISA wiretaps to see why the risk of overbroad collection is especially high here.
In part because courts have suggested that the constraints of the Fourth Amendment bind more loosely in the foreign intelligence context, FISA surveillance is generally far more sweeping in its acquisition of information.