Earlier quoted context omitted.
The front door is a less useful metaphor than your safe. We have safes in addition to locked front doors because it's accepted getting into the house is generally not that hard, whether you be law enforcement or a criminal.
A warrant is just as effective against nearly all safes. I have little doubt that if a safe was in FBI custody as long as the San Bernardino shooter's phone has been, the FBI would have been able to legally and physically get whatever was inside. The FBI simply wants the digital world to mirror the physical world and a 100% unbreakable physical lock is almost impossible to produce in the physical world. It is easy to…
https://www.aclu.org/blog/free-future/one-fbis-major-claims-...
[EDIT for added link]