An effective barrier is making it IMPOSSIBLE for a government request for data to be fulfilled - such as end-to-end encryption where the intermediary never has the key, like Whatsapp has done. This is easiest if implemented into a new system from the beginning design of its architecture.

It completely removes the need to waste person-hours attempting to fulfill a "wiretrap" request, whether from a warrant or FISA-court type thing, if the request is impossible due to lack of crypto keys. And at least at present completely legal unless the US passes laws outlawing crypto.