Today the U.S. Supreme Court agreed to hear a major case that has the potential to reshape the face of Fourth Amendment jurisprudence in the age of the cell phone.

At issue in Carpenter v. United States is whether the FBI violated the Fourth Amendment when it obtained, without a search warrant, the cell phone call and location records of several suspected armed robbers. By pinpointing the cellular towers that handled the suspects' calls during the time periods in which the robberies were committed, federal officials were able to trace back the suspects' movements and link their whereabouts to their alleged crimes.

According to the U.S. Court of Appeals for the 6th Circuit, which ruled in favor of the government's warrantless activity in this matter, "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 6th Circuit justified its decision by citing U.S. Supreme Court precedent. For example, in Katz v. United States (1967), the Court held that "what a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection." Even more significantly, in Smith v. Maryland (1979), the Court ruled that "a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties."

Otherwise known as the "third-party doctrine," this legal standard has proven to be a great boon to law enforcement. But it has also placed certain Fourth Amendment rights on the chopping block. The question for the Supreme Court in Carpenter v. United States is whether the fundamental right to be free from unreasonable search and seizure can be squared with the vast warrantless search powers that law enforcement officials now routinely enjoy.

Oral arguments in the case are likely to be held at SCOTUS this fall. Will the Court cabin the third-party doctrine, curb the power of the police, and recognize broader Fourth Amendment protections for cell phone users?

At least one member of the Court seems inclined to do all of the above. As Justice Sonia Sotomayor remarked in the 2012 case of United States v. Jones, "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.