With iOS 8, Apple has implemented a new “zero-knowledge” security policy when it comes to iOS devices. In part, that means “it’s not technically feasible for [Apple] to respond to government warrants.” At The Volokh Conspiracy, Orin Kerr points out that the government might not be willing to accept that scenario.
1) The most obvious option would be follow the example of CALEA and E911 regulations by requiring cellular phone manufacturers to have a technical means to bypass passcodes on cellular phones.
2) A second option would be to enact a new law severely punishing a target’s refusal to enter in his passcode to decrypt his phone.
3) A third option would be to impose data retention laws.