THE framers of America’s constitution knew nothing about mobile phones, but they knew a thing or two about unreasonable searches. In Riley v California, the Supreme Court considered “whether the police may, without a warrant, search digital information on a cellphone seized from an individual who has been arrested.” Unanimously on June 25th, the justices said no, or, to be more precise, very rarely.

David Riley, a member of the Bloods street gang who was sentenced to 15 years to life for attempted murder, and Brima Wurie, sentenced to 262 months on a drug charge, will be happy to hear this. Except in true emergencies where searching a mobile phone could, say, avert a terrorist attack, police prying without a warrant violates the Fourth Amendment’s bar on “unreasonable” searches, the justices decided. Since both Riley and Wurie’s convictions were based on evidence gleaned from such searches, they will be overturned.

Chief Justice John Roberts began by observing how attached Americans have become to their mobile devices: “the proverbial visitor from Mars,” he wrote, might mistake them for “an important feature of human anatomy”. Smartphones can contain “[t]he sum of an individual’s private life...from the mundane to the intimate.” In fact, the ruling reads, thumbing through a mobile phone is potentially far more revealing than “the most exhaustive search of a house”. Without the benefit of “more precise guidance from the founding era,” Mr Roberts explained, the court must weigh individual privacy against “the promotion of legitimate governmental interests”. And since it is usually easy to grab a suspect’s phone, remove its battery or stash it in an aluminium sack (to avert “remote wiping”) and hold onto it pending a warrant, there is no good reason to allow police to rifle through the digital lives of anyone they pull over.

While Riley provides clear guidance for law enforcement, another technology-related case decided on the same day does not. The effects of American Broadcasting Companies v Aereo may not be known for years to come. At issue was whether a startup with a nifty way of delivering broadcast TV programmes to customers for as little as $8 a month violated the 1976 Copyright Act. The Court said yes, by a vote of 6-3.

Aereo had sought to distinguish itself from cable and satellite providers, which have to pay for transmitting programmes created by others. Rather than sending programmes directly to customers’ homes, Aereo captures free, over-the-air broadcasts on wee antennae and transmits them directly to digital recording devices, one per subscriber. Users then access the content on the remote devices via an internet connection, streaming live television with only a few seconds’ delay.

Justice Stephen Breyer, writing for the majority, was unimpressed with Aereo’s attempt to set itself apart. “For all practical purposes,” he wrote, Aereo is “a traditional cable system”. It uses its own equipment, transmits copyrighted material to users’ homes and lets them watch the shows “virtually as the programming is being broadcast”. Fancy technology does not give Aereo immunity from copyright law.

Justice Antonin Scalia, writing in dissent, explored the wider implications of Aereo’s loss. Aereo is more like a “copy shop” than a cable system, he wrote. Rather than “provide a prearranged assortment of movies and television shows,” Aereo allows customers to choose freely available shows they want to digitise; “subscribers,” in short, “call all the shots.” The majority’s ruling, Justice Scalia charged, paves the way for similar curbs on cloud-based technologies that hundreds of millions of Americans rely on every day—from Dropbox to music-streaming services. “The Court vows that its ruling will not affect cloud-storage providers and cable-television systems,” Justice Scalia warned, “but it cannot deliver on that promise.” The boss of Aereo, Chet Kanojia, wrote that the ruling may have a “chilling” effect on the technology industry. Whether or not this proves to be the case, it will force Aereo to rethink its novel business model.