FBI pins its protests over phone encryption on criminal case involving fatally beaten toddler

FBI Director James Comey says encrypting data stored on smartphones and computers could hurt criminal investigations. He cites as proof cases in which access to information on cellphones played a critical role in investigations.

One case, involving a 2-year-old Los Angeles girl who was beaten to death, provides a powerful, compelling argument. Not as persuasive are cases in which the authorities were tipped off or even solved the crime through means other than examining data they took from victims or suspects.

The struggle to justify the FBI's complaints about new phone encryption underscores the uphill fight facing the Obama administration in the wake of disclosures by former National Security Agency analyst Edward Snowden.