Supreme Court narrowly protects privacy of cellphone location data
26 June 2018
In a 5-4 ruling, the Supreme Court of the United States issued an opinion Friday holding that a criminal defendant’s cellular phone location data, obtained without a warrant, cannot be used as evidence against him.
Chief Justice John Roberts wrote the majority opinion, emphasizing the ubiquity of cellular phones in modern life, as well as the intimate nature of the location data held by carriers. If reviewed without a warrant, such data would allow the government to conduct “near perfect surveillance, as if it had attached an ankle monitor to the phone’s user”—not only prospectively, but for a period of up to five years prior.
Roberts joined the so-called liberal bloc of justices Elena Kagan, Sonya Sotomayor, Ruth Bader Ginsburg and Steven Breyer, providing a majority with an unusual line-up. It is often Anthony Kennedy who serves as a “swing” vote between the liberal and reactionary blocs. It is only the second time Roberts has written a 5-4 opinion while joining the liberal bloc. This occurred in the highly political decision on Obamacare (the Affordable Care Act) in NFIB v. Sibelius.
Friday’s decision concerned Timothy Carpenter, convicted of a spree of robberies across Michigan and northern Ohio. The FBI had used cellphone location data, generated when a phone connects to a nearby radio tower and uses its service, to follow Carpenter’s movements for 127 days. The government collected a total of 12,898 location points in Carpenter’s records, or an average of 101 each day.
The FBI became aware of Carpenter in 2011 when some of his accomplices were arrested and gave up his name and phone number. Instead of applying for a warrant, which would have been…