WikipediaWikipediaYesterday's revelations about mass NSA snooping were quickly followed by assurances from administration officials and members of Congress that it was all perfectly legal. How can that be true?

The NSA's collection of telephone records from Verizon was based on Section 215 of the PATRIOT Act, which authorizes the director of the FBI or his designee to apply for a secret court order requiring production of "any tangible things (including books, records, papers, documents, and other items) for an investigation to protect against international terrorism or clandestine intelligence activities." To obtain the order, the government need only "specify" that the records are part of such an investigation and that it is not targeting a U.S. citizen or legal resident "solely upon the basis of activities protected by the first amendment." Those requirements are considerably less demanding than the "probable cause" that the Fourth Amendment specifies as the standard for search warrants, and the resulting court orders can be much broader—in this case, seeking information on all phone calls, domestic and international, handled by Verizon (and it seems safe to assume that other carriers have received similar orders). But doesn't that sort of dragnet violate the constitutional rights of Verizon's customers? Not according to the Supreme Court, which has repeatedly said people have no Fourth Amendment rights in connection with records held by third parties, on the theory that they have voluntarily divulged that information and therefore no longer have a reasonable expectation that it will remain private. The level of protection accorded such records is therefore determined by statute.

Even at a time when people's records typically were kept on paper in filing cabinets, that doctrine did not make much sense. The Fourth Amendment, after all, protects people's "papers" as well as their "persons," "houses," and "effects," from "unreasonable searches and seizures." Why should that protection hinge on the location of those papers? The fact that you have disclosed information to a particular person or business for a particular purpose does not necessarily mean you have no legitimate interest in shielding it from government snooping. Nowadays people's "papers," including a great deal of sensitive information, are commonly kept on remote servers, which has created an anomalous situation in which the government needs a warrant to listen to a phone call or open a letter but arguably can read email at will (unless it happens to be stored on your own computer). Proposed amendments to the Electronic Communications Privacy Act would clarify that a warrant is always required to look at people's email, but the privacy of this ubiquitous method of communication will still hinge on legislation passed by Congress instead of the Fourth Amendment.

The same appears to be true of the data collected by the NSA as part of its PRISM program, which reportedly involves direct access to the servers of Microsoft, Yahoo, Google, Facebook, PalTalk, AOL, Skype, YouTube, and Apple. The Washington Post reports that the NSA is "extracting audio and video chats, photographs, e-mails, documents, and connection logs that enable analysts to track foreign targets." The administration's defense of this program rests mainly on the claim that it targets foreigners, with collection of Americans' personal information merely "incidental." Director of National Intelligence James Clapper assures us that PRISM "cannot be used to intentionally target any U.S. citizen, any other U.S. person, or anyone located within the United States." I don't know about you, but I do not feel reassured upon hearing that Americans' privacy is compromised only by accident. In any case, whatever privacy protection Americans enjoy with respect to most of this online material, because it consists of information held by third parties, would be based on statute. And what Congress gives, Congress can take away.

At least one member of the Supreme Court finds this situation alarming. Concurring in U.S. v. Jones, the 2012 case in which the Court said tracking a suspect's car by attaching a GPS device to it amounts to a "search" under the Fourth Amendment, Justice Sonia Sotomayor urged her colleagues to rethink the third-party doctrine:

It may be necessary to reconsider the premise that an individual has no reasonable expectation of privacy in information voluntarily disclosed to third parties. This approach is ill suited to the digital age, in which people reveal a great deal of information about themselves to third parties in the course of carrying out mundane tasks. People disclose the phone numbers that they dial or text to their cellular providers; the URLs that they visit and the e-mail addresses with which they correspond to their Internet service providers; and the books, groceries, and medications they purchase to online retailers. Perhaps, as Justice Alito notes, some people may find the "tradeoff " of privacy for convenience "worthwhile," or come to accept this "diminution of privacy" as "inevitable," and perhaps not. I for one doubt that people would accept without complaint the warrantless disclosure to the Government of a list of every Web site they had visited in the last week, or month, or year. But whatever the societal expectations, they can attain constitutionally protected status only if our Fourth Amendment jurisprudence ceases to treat secrecy as a prerequisite for privacy. I would not assume that all information voluntarily disclosed to some member of the public for a limited purpose is, for that reason alone, disentitled to Fourth Amendment protection.

If the controversy over NSA surveillance leads Congress to increase statutory protections for electronic privacy, that would be good. If it leads the Court to a new understanding of the the Fourth Amendment's relevance in this area, that would be better.

Addendum: The Electronic Privacy Information Center cites three reasons for concluding that the Verizon order, given the enormous breadth of the information it required, was not in fact authorized by statute. First, the order was supposed to be based on "reasonable grounds to believe that the tangible things sought are relevant to an authorized investigation," something the government could not have done with respect to millions of Verizon customers. Second, the government is not supposed to conduct an investigation "solely upon the basis of activities protected by the First Amendment." Yet for the vast majority of people whose information was collected, the only basis was the fact that they made phone calls, an activity protected by the First Amendment. Third, investigations must comply with "guidelines approved by the Attorney General under Executive Order 12333," which instruct investigators to "use the least intrusive collection techniques feasible within the United States or directed at U.S. persons abroad."