Thank you, the bit I didn't appreciate was the signing of Apple's software to do this. So yes, only Apple can (but wont) do this, thus making it secure provided Apple don't or aren't forced to change their mind.
Once the government can force apple to create software against their will, why do you think they won't also force Apple to hand over signing keys that will let them target any phone they want? I don't see how the slippery slope can end at one phone (and that slope is already sliding to encompass dozens of phones - when it reaches hundreds or thousands of phones, the government is going to decide that they need to be able to target phones on their own, without Apple in the way)
