What does the USA do about WhatsApp? Do they really tolerate end to end encryption they cant subpoena the company for...or does the NSA have a big fat pipe into the WhatsApp data-center?
For high enough value targets the NSA is probably happy to compromise the endpoints.
I guess the recent case with the FBI and the iPhone shows what will happen if they want messages badly enough.
If they pin then the NSA would have to actually have access to the data center and doing that much without getting noticed is quite hard.