On August 2, 2009, San Diego police officers stopped a red Oldsmobile for expired tags. The driver, David Leon Riley, also had an expired license. The officers impounded and searched the vehicle, finding two concealed and loaded firearms. Riley was arrested.

During the search, one of the officers noticed Riley wore insignia of a gang known as the “Lincoln Park Bloods.” The officer took Riley’s cellphone and examined its contents, finding information that confirmed his gang affiliation.

Two hours later, a detective specializing in gang investigations looked through the cell phone’s contents, including videos and photos. Riley was later charged with an unrelated shooting that had taken place about three weeks prior to his arrest, based in part on images found on Riley’s cellphone of him standing in front of a car that the police suspected had been involved in a shooting. In court, Riley moved to have this evidence suppressed and argued that the search violated his Fourth Amendment rights.

The case eventually reached the Supreme Court of the United States in 2014, where the state of California relied on Court precedent that outlined warrantless search exceptions. In Chimel v. California (1969) and United States v. Robinson (1973), the Court held that officers may conduct a full search of the arrestee and the area under the arrestee’s immediate control to protect officers' safety and preserve evidence. In Riley’s case, however, the Court ruled that these exceptions did not apply.

Doug Godfrey

Professor, iit chicago-kent college of law

In a unanimous decision, the Court ruled in Riley v. California that the warrantless search of Riley’s cell phone upon arrest constituted an unreasonable search and seizure. While the Court limited warrantless search exceptions, it claimed consistency with Chimel and Robinson. Since digital data could not be used to harm the officer, and its contents could be preserved from deletion, the rules permitting a warrantless search did not extend to cellphones.

Chief Justice John Roberts, who authored the majority opinion in Riley, made it clear that just because an “arrestee has diminished privacy interests does not mean that the Fourth Amendment falls out of the picture entirely.” He acknowledged that this decision will have an impact on the ability of law enforcement to combat crime, but “[p]rivacy comes at a cost.”

By carving out narrow exceptions to the law, the Roberts Court has established a limit on what police can do in searches incident to arrest without challenging current precedent. The Court's approach in Riley is consistent with its earlier ruling in Arizona v. Gant, a 2009 decision that held police may not search a vehicle of its recent occupant since the arrest occurred after the person had already left the car. This 5-4 ruling limited earlier precedents. In New York v. Belton (1981), the Court allowed police to search the passenger compartment upon arrest, and in Thornton v. United States (2004) police were permitted to search the vehicle of a person they arrested, even though they did not make contact with him until after he left the vehicle.

A police officer making an arrest

In his concurring opinion for Gant, Justice Scalia advocated for simply abandoning “the Belton-Thornton charade of officer safety and overrule those cases.” The Court’s majority opinion, authored by Justice John Paul Stevens, clarified that this decision did not overrule previous cases but further defined the circumstances under which a warrantless search is allowed.

“[W]e hold that Belton does not authorize a vehicle search incident to a recent occupant’s arrest after the arrestee has been secured and cannot access the interior of the vehicle.” Arguing consistency with Thornton, the Court reasoned that “circumstances unique to the automobile context justify a search incident to arrest” when an officer has a reasonable belief the evidence of the arresting offense may be found in the vehicle.

Justice Samuel Alito, in his dissent, stated the Court could not overrule Thornton and Belten and argued its decision, as it was, would “cause the suppression of evidence gathered in many searches carried out in good-faith reliance on well-settled caselaw.”

The Roberts Court has sought to define what law enforcement is permitted to do in searches incident to arrest without limiting precedent. The caveats outlined in Riley and Gant pose limits to police without walking back existing warrantless search exceptions. Current caselaw under Chambers v. Maroney (1970) allows police to conduct a warrantless search of the vehicle after it is moved to police precinct following an arrest. The ruling expanded the “automobile exception” established in Carroll v. United States (1925), which allowed police to conduct a warrantless search of a vehicle because its mobility made it impractical to get a warrant.

While the Roberts Court has not expanded the scope of law enforcement as Chambers did with Carroll, as it stands, law enforcement is afforded many warrantless exceptions for searches incident to arrest. The Court, as seen in Riley and Gant, has refused to bring into question those rulings.