No, there isn't -- there is no such evidence that our elected officials are being coerced by the NSA.
Let me say it again, if such proof is revealed then it would be absolutely terrifying for everybody involved and all over the news (be it MSM or social or whatever). As it stands now there are only claims, and there is a distinct lack of evidence and facts surrounding such claims.
Now, with regards to blackmailing our elected officials, I think we can put it simply as such: the fear of just the possibility that we might be blackmailed is enough to cause self-censorship. This is a historical truth and accepted as self-evident.
That said, our elected officials are no less victims than we are. They are spied on as much as -- if not more than -- us.
Please acknowledge this one thing, if you will acknowledge anything in my post: our elected officials are no less victims than we are.