A U.S. Court of Appeals ruling for the Fifth Circuit has declared that geofence warrants, a controversial law enforcement tool, are unconstitutional. This decision, issued on Friday, marks a significant shift in how police can use digital location data to investigate crimes across Louisiana, Mississippi, and Texas.

The Fifth Circuit's ruling states that geofence warrants are "categorically prohibited by the Fourth Amendment," which protects citizens against unwarranted searches and seizures. This ruling effectively bans the use of these warrants in the three states within the court’s jurisdiction, a move that has been widely praised by civil liberties and privacy advocates.

The Fourth Amendment to the United States Constitution is a fundamental component of the Bill of Rights that protects citizens from unreasonable searches and seizures by the government. It mandates that any search or seizure conducted by law enforcement must be reasonable and, in most cases, supported by a warrant issued by a judge. This warrant must be based on probable cause and must specifically describe the place to be searched and the persons or things to be seized.

Geofence warrants, often referred to as “reverse” search warrants, allow law enforcement to draw a geographic boundary—such as around a crime scene—and request data from companies like Google. These companies then provide information on all devices within that area during a specified time frame, which can include data from innocent individuals who happened to be in the area.

In the context of geofence warrants, the Fourth Amendment is particularly relevant because these warrants involve broad, indiscriminate searches of digital data that may include information about individuals who are not suspected of any wrongdoing.

Critics have long argued that geofence warrants are overly broad and infringe on privacy rights by sweeping up data on individuals who have no connection to the crime. The case that prompted the Fifth Circuit’s ruling involved an armed robbery of a U.S. Postal Service worker in Mississippi in February 2018. Police used a geofence warrant to gather location data from Google, which ultimately led to the identification of suspects.

In a noteworthy contrast, just last month, the Fifth Circuit’s decision differed from this ruling issued by the Fourth Circuit. The Fourth Circuit, which covers North Carolina, Virginia, and West Virginia, found that accessing Google’s location data did not constitute a search, thereby upholding the legality of geofence warrants in those states.

However, the Fifth Circuit's opinion emphasized that requesting data from Google’s extensive location database does indeed qualify as a search under the Fourth Amendment. The court argued that because the search involves scanning the entire database without knowing who the target is or whether the search will yield results, it lacks the specificity required by the Constitution.

The ruling stated, “This search is occurring while law enforcement officials have no idea who they are looking for or whether the search will even turn up a result. Indeed, the quintessential problem with these warrants is that they never include a specific user to be identified, only a temporal and geographic location where any given user may turn up post-search. That is constitutionally insufficient.”

Despite declaring geofence warrants unconstitutional, the Fifth Circuit upheld the defendant’s conviction in the Mississippi case, citing that the police acted in good faith when seeking the warrant. The court noted that the warrant was obtained with the guidance of other agencies and that the use of geofence warrants was a relatively novel legal issue at the time.

In response to the increasing scrutiny, Google announced late last year that it would begin storing users' location data on their devices rather than in its servers, which may limit the effectiveness of geofence warrants going forward.

The contrasting rulings by the Fifth Circuit and Fourth Circuit Courts of Appeals on the constitutionality of geofence warrants could set the stage for a U.S. Supreme Court review. When different federal appellate courts issue conflicting decisions on the same legal issue, it creates a "circuit split." The Supreme Court often steps in to resolve such splits to ensure uniformity in the interpretation and application of federal law across the country.

In this case, the differing interpretations of the Fourth Amendment's application to geofence warrants could lead the Supreme Court to review the issue to provide clarity on whether and how these warrants can be used constitutionally by law enforcement. The high court's decision would have significant implications for law enforcement practices, privacy rights, and the legal standards governing digital data searches in the United States.

Given the importance of the Fourth Amendment and the growing use of digital data in criminal investigations, the Supreme Court might see this as a critical issue worthy of its attention. A ruling from the Supreme Court could establish a national standard on the use of geofence warrants, resolving the current legal uncertainty created by the conflicting appellate court decisions.