The Supreme Court has ruled in the closely watched Carpenter v. United States
case, which questioned the constitutionality of warrantless location
surveillance, a widespread practice among US law enforcement and
surveillance agencies.
Government agencies have long harvested bulk location data (and other
forms of metadata) from mobile phone carriers without a warrant, relying
on the “third party doctrine,” a 1970s vintage legal principle that
says that your right to privacy ends once you provide information to
third parties like phone companies. The cases that developed the third
party doctrine were about things like calling records from payphones,
but over the decades, the US government stretched this narrow crack in
the Fourth Amendment into a Grand Canyon-sized crevasse.
A series of cases brought before the Supreme Court in recent years has
begun to reverse the trend, and Carpenter is the latest and most
sweeping narrowing of government wireless surveillance powers.
In a 5-4 ruling, the Supremes held that “the exhaustive chronicle of
location information casually collected by wireless carriers” is
fundamentally different from the data that the third-party doctrine
encompasses – the whole decision and its notes runs to 119 pages,
and experts will be parsing out the judgment in the days to come,
analyzing the parts of the US’s warrantless surveillance program that it
leaves intact.
