Re "Doesn't sound very constitutional to me. What have we become?"
In the past the GCHQ would do everything it could to stay out of court closed or open. No methods, no logs, no experts with no pasts to confirm documents as found, decrypted.
Any information gathered would have to be undergo parallel construction by other services or methods to remove any signal or decoding aspects.
The problem for the US is the very public talk of " all the phone records into a lockbox" to be reconstructed anytime over a persons life.
Within the US there is limited access to the top political policy setting. Other groups within the US domestic and more international law enforcement may not like a signals conversation with the public.
What the GCHQ only had to fend off every few decades in the UK with policy makers is now very public in the USA - total mastery of global telecommunications network with generational storage.
Slowly the other aspect is becoming more public too: "European Court Says CIA Ran Secret Jail in a Polish Forest" (July 24, 2014)
http://www.nytimes.com/reuters...
Its the age old use of signals intelligence - never tell the public and it is perfect. The problem for the USA is so many groups are now using signals intelligence that they all want the big wins in public and closed trials.
The problem is once signals intelligence gets out in court at a city, state, federal level - the magic stops. Every court connected member of the press, legal profession, law enforcement suddenly has a story to sell, tell or whisper.
Anybody who needs to know about crime and signals intelligence can then just buy the methods and drop out.
What did the UK learn early on? Dont give political leaders raw information about the Soviet Union - ever. Dont go to court over spies - ever.
Dont go to court over leaks, whistleblowers or tell all books or for peace activists.
The UK knows the stories then just drop away from the front pages and drift off into academic books with very limited print runs.
The real unknown is the US cyber industrial complex with products to sell, rent and look after in every city and state if lobbied.
The West has become one big signals intelligence marketplace and laws need to be relaxed to enjoy new sales
:)