I follow this issue and read a lot about it, and I'm still not sure what powers the NSA has, other federal and state agencies have, under what laws, and which h

I follow this issue and read a lot about it, and I'm still not sure what powers the NSA has, other federal and state agencies have, under what laws, and which have been restricted. It would be a valuable public service -- more than all the newspaper articles and press releases -- if someone who knows all that could make a simple table: Agency | Power | Limits | Legal authority