Suspect must use finger to unlock phone, as debate shifts over device privacy

For police the warrant rule is now one of two obstacles standing in the way of a cell phone search. The other is the new prevalence of passcodes, which most people use to lock their phones, and which are harder to get around than ever before thanks to expanded encryption. The result is a new controversy over when cell phone users must assist the police.

Recent legal battles over cell phone searches have focused (correctly) on the Fourth Amendment, which is how the US Constitution protects people against unreasonable search and seizure -- specifically, by requiring cops to get a warrant for performing most type of searches. In light of the Supreme Court’s recent ruling, however, that question has been largely put to rest. Now the debate is turning instead to the Fifth Amendment, which protects suspects from having to testify against themselves. While the historical right to “plead the Fifth” is well understood (it prevented soldiers from getting a confession by beating someone up), its role when it comes to cell phones is less obvious.