What case ruled that police officers must have a warrant to search digital contents of a cell phone?

The case that established the requirement for police officers to obtain a warrant before searching the digital contents of a cell phone is Riley v. California. This landmark decision, issued by the U.S. Supreme Court in 2014, highlighted the privacy interests and the vast amount of personal information contained within modern cell phones. The court determined that the search of digital data on a cell phone is fundamentally different from traditional searches and requires a warrant under the Fourth Amendment.

Riley emphasized that cell phones hold immense amounts of personal data that can reveal a person's private life, making the protective requirement of a warrant essential to safeguard individual privacy rights. The ruling set a clear precedent that police must respect these privacy rights before accessing data stored on a cell phone, reflecting a significant evolution in how the law views digital privacy compared to past cases.

The other cases listed address different legal principles not directly related to searches of digital content on cell phones.