[Zak]

The NSA secured an order from the FISC directing Verizon to turn over metadata on all calls made within the US, which includes data about the location of their customers' mobile phones. The Supreme Court has ruled that long-term tracking requires a warrant. The decision was unanimous, but split as to reasoning. The majority held that such tracking without a warrant violates the 4th amendment. It is quite likely that obtaining phone records for the purpose of tracking location has the same legal status.