The US Supreme Court is debating two cases today that may decide whether or not the cops can search people’s mobile phones without a warrant.

Defendants in two different cases, David Riley and Brima Wurie, are arguing that their convictions should be overturned because evidence from their phones was taken and used in court despite the fact that the mobile devices were searched without a warrant.

As it stands, police are only supposed to be able to search for items as they make an arrest for two reasons: officer safety or the need to gather evidence that could be disposed of easily. This has allowed cops to look through wallets, address books and other personal items.

But privacy advocates and criminal defence lawyers supporting Wurie and Riley have said that mobile phone data is not a safety risk and can easily be saved. They argue that because phones contain additional personal information like photos, videos and social media information, they shouldn’t be searched without a warrant.

"Allowing police officers to search a person's cell phone without a warrant following an arrest would be a substantial infringement on privacy, is unnecessary, and unreasonable under the Fourth Amendment," the Electronic Privacy Information Centre wrote in a brief to the court.

Lawyers for the US government have told the court that searching a mobile phone is no different to other warrantless searches of items on a person at the time of their arrest. They also argue that some information on phones is deleted after a certain time period or could be deleted remotely, so it’s vulnerable to being discarded.

"While technology has increased the amount of information an individual may practically choose to carry, neither the form nor the volume of the information at issue here provides a sound basis for redrawing clearly established Fourth Amendment lines," Kamala Harris, the attorney general for California, said in court papers.

The cases at hand have had different outcomes. In the Riley case, the defendant was convicted of three charges over an incident in 2009 where shots were fired at an occupied car. Police linked Riley to the crime partly because of a photograph on his smartphone that showed him posing in front of a similar vehicle. Riley’s conviction was upheld by an appeals court in California.

An appeals court in Boston overturned Wurie’s conviction for drugs and firearms charges however, ruling that police should not have searched Wurie’s phone without a warrant. In a major difference between the cases, Wurie’s mobe was not a smartphone and was only used to find a phone number.

The Supreme Court will need to decide whether the Fourth Amendment, which forbids unreasonable searches, requires police to get a court’s approval for mobile phone searches. The nine-judge ruling is expected by the end of June. ®