I learned of this concept in one of my geography classes called, "Not in my backyard." Basically what it means is that people refuse to act against a bad practice until it is done to them. We studied it in the form of pollution, waste, etc. But I think it certainly applies to concepts like spying, taxation and other government activities.

Spying on the Senate is a much scarier proposition than foreign governments or individuals. Our democratic system is based upon Congress being the ultimate authority in the land. This authority is even higher than the constitution itself, which is how they are able to amend it.

If they cannot maintain control of the executive branch then our democracy is lost.

The very purpose of a clandestine intelligence service is to obtain the facts and analysis necessary to advance foreign policy objectives.

Within that context, the expectation is that the advancement of those goals is for the benefit of your own citizens (and possibly at the expense of other people).

This is very different than advancing policy goals at the expense of your own citizens.

Give me money and I'll make you rich. Don't mind that I am spying on your allocators of money. More money please. My friends that I bought with your money want to sell crack on your streets, thats cool right? How about some heroin? More money please, I'm having trouble tapping the lines of everyone who has something bad to say about me. Oh I mean us.