I think that both Trump and Cruz believe that the "unlocking" solution can be applied to just this one phone. Cruz has said as much. Trump would probably say as much after being briefed by his "this is conservative and that isn't" team.
From what I've read, any solution would be applicable to all Apple phones, and the government, or anyone else, could apply the same solution, disable the data eradication functionality, and work as long as they like on cracking the password on any Apple phone.
I really don't think that Apple is trying to protect the terrorists. If there was a solution that would allow access to JUST THIS ONE PHONE, they'd provide it.
Apple only needs to give the government a read out of what is in the phone.
If the phone yielded to saying supercalifragilisticexpialidocious over it, Apple wouldn’t need to tell anyone about that.