All the big providers seem to have this odd model of "We use E2E encryption, but we do unencrypted backups by default". iMessage and Whatsapp are both this.

All the big providers seem to have this odd model of "We use E2E encryption, but we do unencrypted backups by default". iMessage and Whatsapp are both this. Since you only need one participant in a conversation to not enable backup encryption, I would guess that law enforcement has cleartext access to over 99% of messages sent by americans. The next question is do they only have access to certain messages on request, or do they get a near real time feed. Things like this[1] suggest they had a real time feed of all messages, and I doubt they would be allowed to lose that ability. [1]: https://blog.encrypt.me/2013/11/05/ssl-added-and-removed-here-nsa-smiley/ https://blog.encrypt.me/2013/11/05/ssl-added-and-removed-her...