In 1979 the U.S. Supreme Court ruled that law enforcement officials do not need a search warrant in order to obtain a suspect's telephone call records from that suspect's telephone company. According to the Court's opinion in Smith v. Maryland, "a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties."

Also known as the third-party doctrine, this rule raises some significant questions in the age of the smart phone. After all, today's wireless companies don't just have a record of the numbers you dialed (or texted), they also have a record of your location when you dialed (or texted) them. Is that sort of personal information entitled to any meaningful protection under the Fourth Amendment?

The Supreme Court now has the opportunity to provide some fresh answers. On May 11 the justices will meet in their next private conference to consider the latest batch of cases up for possible review. Among those petitions are five cases that effectively ask the Court to give the third-party doctrine a second look. A definitive ruling by the Court against the government in any one of those five cases could reshape the landscape of Fourth Amendment law.

One of the five petitions deals with a case called Carpenter v. United States, a matter in which the FBI obtained, without a search warrant, the cell site data of several alleged armed robbers. Put differently, the authorities obtained the records of the various cell phone towers that handled the calls made by the suspects. The FBI then used that information to track the suspects' movements and pinpoint their locations during the times in which the robberies were committed.

According to the U.S. Court of Appeals for the 6th Circuit, which ruled in favor of the government's actions, "although the content of personal communications is private, the information necessary to get those communications from point A to point B is not." And "cell-site data," that court said, just "like mailing addresses, phone numbers, and IP addresses [are] information that facilitate personal communications, rather than part of the content of those communications themselves. The government's collection of business records containing these data therefore is not a search."

The petition in Graham v. United States presents a similar scenario. Here the government also obtained the cell site data of an alleged armed robber without first obtaining a search warrant. But the government initially lost this case before a three-judge panel of the U.S. Court of Appeals for the 4th Circuit, which found the government's actions to be unconstitutional under the Fourth Amendment. However, a full panel of 4th Circuit judges later reversed that decision.

"The question before us," the full 4th Circuit panel said, "is whether the government invades an individual's reasonable expectation of privacy when it obtains, from a third party, the third party's records, which permit the government to deduce location information." Unfortunately for the suspect, the ruling concluded, "under the third-party doctrine, an individual can claim 'no legitimate expectation of privacy' in information that he has voluntarily turned over to a third party." That suspect, Aaron Graham, is now urging the Supreme Court to overturn the 4th Circuit's ruling against him on the grounds that "mobile phone technology, including the use of passively generated [cell site location information], has outstripped the reasoning of Smith."

The three other related petitions now before SCOTUS proceed along similar lines. "Does the Fourth Amendment require law enforcement to obtain a warrant to acquire [cell site location information]?" asks Jordan v. United States. Did the U.S. Court of Appeals for the 7th Circuit get it wrong when it held "that individuals have no reasonable expectation of privacy in information held by a third party," queries Caira v. United States. Must law enforcement "secure a warrant to obtain real-time cellular-phone location data," inquires Rios v. United States.

All five of these pending petitions center on the same fundamental conflict: namely, the conflict between the Fourth Amendment right to be free from unreasonable search and seizure and the third-party doctrine's vast grant of warrantless search and seizure powers to law enforcement agencies.

Will the Supreme Court agree to hear one or more of these cases at its next private conference? At least one member of the Court seems inclined to do so. Writing in concurrence in the 2012 case of United States v. Jones, Justice Sonia Sotomayor wondered whether "it may be necessary to reconsider the premise that an individual has no reasonable expectation of privacy in information voluntarily disclosed to third parties." As Sotomayor noted, "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…. 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."

Stay tuned.