It's not that every intelligence agency is evil. It's not that they never do any good at all. We want to have some level of intelligence-gathering. We want to be able to investigate criminals; we want to be able to respond to military threats. But that's a very far cry from watching everyone in society without regard to their guilt or innocence -- to the mass surveillance of entire populations rather than individual people.
-- Fugitive former NSA contractor Edward Snowden in a Q&A session with a London audience set up by Amnesty International, 2 June 2015