Skip Navigation

Brief: Warrantless Cellphone Searches Should Be Prohibited

Law enforcement officers should not be allowed to search the contents of a cellphone without a warrant when they arrest someone, the Brennan Center and the NACDL argue in an amicus brief.

March 11, 2014

Brennan Center, National Association of Criminal Defense Lawyers file brief in privacy case

Law enforcement officers should not be allowed to search the contents of a cellphone without a warrant when they arrest someone, argue the Brennan Center for Justice at NYU School of Law and the National Association of Criminal Defense Lawyers (NACDL) in an amicus brief filed Monday.

In Riley v. California, the U.S. Supreme Court will consider whether cellphones fall under the “search incident to arrest” doctrine — an exception to the Fourth Amendment that permits police to search an arrestee for weapons that could harm the officer or for destructible evidence. Cellphones, the Brennan Center and NACDL argue, pose no threat to officer safety. The risk of loss of data is also low. Cellphones can, however, reveal immense amounts of personal information and examining them without a warrant is an undue invasion of Americans’ privacy.

“Our online lives have become just as private and personal as our physical lives,” said Bronson James, Counsel for the National Association of Criminal Defense Lawyers. "Our smartphones are the doorways to our digital homes, where we keep calls, texts, emails, documents, photographs, financial and health records, and all manner of private information. An officer should not be able to access one’s entire digital life without a warrant. Cellphone searches must be regulated by the courts under the Fourth Amendment.​"

“Given the enormous privacy implications of cellphone searches, a neutral magistrate should decide when and how they can be searched, not a cop in the heat of an investigation,” said Michael Price, Counsel at the Brennan Center for Justice’s Liberty and National Security Program. “The warrant requirement ensures appropriate judicial oversight of all cellphone searches and preserves the delicate balance between privacy and security in law enforcement investigations.”

“Once in the hands of law enforcement, cellphone data may be kept on government databases and shared among countless agencies and government officials for years,” said Amos Toh, Katz Fellow at the Brennan Center. “We need to make sure that police collect it only when they are entitled to do so, and not simply whenever they arrest someone.”

To schedule in an interview, contact Seth Hoy at or 646–292–8369.


In Riley v. California, San Diego police officers pulled over David Leon Riley for driving with expired license plate. The police found firearms in his car, placed him under arrest and seized his cellphone. The police subsequently went through and downloaded data from his the phone without a warrant while “looking for evidence.” Prosecutors relied on pictures and videos found on the cellphone to support their allegation that Riley had committed crimes for the benefit of a criminal street gang, exposing Riley to a significantly enhanced sentence.

When the police arrest someone, they are allowed to search the person’s body for weapons and evidence. But whether they can also rummage through the contents of the person’s cell phone – including his or her text messages, e-mails, call-logs, pictures and videos – without a warrant is something the Supreme Court will confront in this case. Riley is poised to set another baseline for privacy and Fourth Amendment protection in the digital age. 

  • Read more about the case here.