Skip to main content
Please enter a legal issue and/or a location
Begin typing to search, use arrow keys to navigate, use enter to select

Cell Phone Privacy and Warrant Requirements

There are more mobile phones than people in the United States, according to most estimates, with many users having multiple cell phones. Most of these devices are internet-connected, GPS-enabled "smart" phones with the ability to track our movements, online purchases, personal relationships, and much more. But while we know -- or should know -- of such exposure, we still have a certain expectation of privacy under the law.

But where, exactly, does the line fall when it comes to cell phone privacy and warrant requirements? Can the government simply collect what we share, even if we're not fully aware of what we're sharing, or are there limits?

This article explores the basics of cell phone privacy with respect to the Fourth Amendment right against unreasonable search and seizure, the third-party doctrine, and the changing nature of what's required for a warrant of cell phone records.

Fourth Amendment Basics

The meaning and scope of the Fourth Amendment has become increasingly complex since it was written into the U.S. Constitution more than 200 years ago. But its fundamental purpose remains: protection against government intrusion into our personal space, whether it's our pockets or our home, without legal justification (which typically comes in the form of a search warrant issued by a judge upon a showing of probable cause).

Certain things that can be observed out in the open or legally obtained from third parties are not considered a "search" within the meaning of the Constitution and therefore don't require a warrant. For instance, an officer who overhears a suspect sharing incriminating information while talking on their cell phone in public can use that information as evidence. The police cannot, however, tap that person's phone without a valid warrant.

But cell phones often raise much more complicated Fourth Amendment issues, such as the difference between data that has been willingly shared and that which is beyond our control or comprehension.

Cell Phone Privacy and the Third Party Doctrine

The "third party doctrine" holds that individuals have a reduced expectation of privacy when it relates to information knowingly shared with a third party, including cell phone companies. Therefore, such information is not protected by the Fourth Amendment and police don't need a warrant to legally access it.

This doctrine was established through the U.S. Supreme Court before the first cell phones were made available to consumers, most notably in the case of Smith v. Maryland (1979), which held that "a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties."

By actively making phone calls, using the global satellite positioning (GPS) network, and saving data to cloud-based servers, we willingly expose ourselves. But since we share an enormous amount of data every day, often unconsciously, it's not always clear just what we're sharing or when. This gray area, further complicated by the ever-increasing sophistication of our digital devices, has generated plenty of debate.

Justice Sonia Sotomayor addressed this in a 2012 case (United States v. Jones) that involved GPS tracking, questioning whether all data subject to the third party doctrine should be exempt from Fourth Amendment protection:

"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."

Carpenter v. United States: Warrant Requirements for Cell Phone Data

Despite the private information that may be revealed to police by GPS coordinates, phone calls placed and received, and other such data, these are services we choose to use. But while the choice to use a cell phone is voluntary, the simple act of turning on your phone doesn't result in the forfeiture of your Fourth Amendment rights. This was decided by the Supreme Court in 2018 (Carpenter v. United States) when it ruled that the use of cell site location information (CSLI) is not subject to the third party doctrine.

CSLI refers to the data generated each time a cell phone connects to a nearby tower. Taken as a whole, this data set can track a person's past and present movements with some degree of accuracy, but less so than that which is tracked by GPS. In the opinion, Chief Justice John Roberts (partially quoting another case) noted the following:

  • First, cell phones and the services they provide are 'such a pervasive and insistent part of daily life' that carrying one is indispensable to participation in modern society.
  • Second, a cell phone logs a cell-site record [CSLI data] by dint of its operation, without any affirmative act on the user's part beyond powering up.

Police also are required to obtain a warrant prior to viewing the contents of a cell phone seized at the time of an arrest, even though non-CSLI data pertaining to that same phone may be accessed from the service provider under the third party doctrine. As mentioned earlier, wiretapping a phone (landline or cell phone) also requires a warrant.

As technology advances, the nature of the third party doctrine likely will be revisited, while other legal questions about warrant requirements for cell phone data are sure to be raised.

Concerned About Cell Phone Privacy? Contact an Attorney

Seeking the counsel and guidance of an experienced lawyer is almost always the right decision when you're facing criminal charges. A legal professional can protect you when the police have violated your Fourth Amendment rights by accessing certain data without a warrant. Get peace of mind and protect your privacy rights by speaking with a local criminal defense attorney.

You Don’t Have To Solve This on Your Own – Get a Lawyer’s Help

Meeting with a lawyer can help you understand your options and how to best protect your rights. Visit our attorney directory to find a lawyer near you who can help.

Or contact an attorney near you:

Next Steps

Contact a qualified criminal lawyer to make sure your rights are protected.

Begin typing to search, use arrow keys to navigate, use enter to select

Help Me Find a Do-It-Yourself Solution

Copied to clipboard

Find a Lawyer

More Options