Making a backdoor that any gov't controls is disastrous. They need to make 2 different software keys; one held by Apple the other by the gov't under control of a VALID court order. The keys cannot be used except in a geo-located place, needs both keys, requires a proper registered iOS device SN. These keys are time sensitive, has to be re-enabled by each entity separately, registered with each entity. Then when these keys are used on the device, it only defeats the 10-try mechanism so the gov't entity must then do its brute force attack.