The NSA and the US Govt is unequivocally to blame. It's not legal as far as they're concerned, they wouldn't be pushing for legislation to give them more power

The NSA and the US Govt is unequivocally to blame. It's not legal as far as they're concerned, they wouldn't be pushing for legislation to give them more power, seek secret courts for unethical interpretations of the constitution or lie and try and hide the scope of their activities (where even members of Congress still have no idea what they're doing) if that was the case. As far as they're concerned they've got all the power and freedom with the influence to push any legislature they need to, and continue unfettered in their mission to track anyone they want to regardless of the constitution, legislation or public opinion.