In light of Edward Snowden’s dramatic revelations about the federal government’s sweeping collection of information about the telephone calls we make, the emails we send, and the social media we use, the very notion of communications privacy is bordering on quaint naivete. Yet, things can always get worse, and the U.S. Supreme Court recently took two cases that threaten to do just that.

On Jan. 17 the court decided to take on the question whether law enforcement officials need a warrant to search the cell phone of a person who has been arrested. Lower courts have split on the issue, with the majority holding that no warrant is required. If the Supreme Court were to adopt that position, that would mean that even minor infractions—such as driving with expired license plates, the underlying offense in one of the cases the court accepted—would open the door to police officers freely exploring arrestee smartphones to read emails, peruse photographs, examine social media postings, track browsing histories, examine financial data, and much more.