I'm going to throw in a suggestion that I haven't otherwise seen made in this discussion. Governments' justification for surveillance is that it's necessary fo

I'm going to throw in a suggestion that I haven't otherwise seen made in this discussion. Governments' justification for surveillance is that it's necessary for fighting terrorism. Okay, I can't say how useful it is for that purpose, I'm not privy to the relevant data; hopefully we can all agree fighting terrorism is a good thing as far as it goes, and it's clear governments believe surveillance is part of that. And if surveillance data was only going to be used against terrorists, that would be fine. The reason many of us are so wary of pervasive surveillance is that we reasonably fear it won't stop there. Would it be politically easier, would governments be more amenable, to attacking that problem instead? To say: fine, the NSA and its counterparts in other countries can have their surveillance, but only if the firewall between the NSA and other branches of government is strengthened to stop the data being used for any purpose except counterterrorism.