Getting caught blackmailing a Congressman would be very, very bad for them. It's far more likely that money from a secret budget ends up in the campaign fund of friendly politicians, or that politicians who do what they want end up with lucrative consulting work after they leave office, much as it is with other industries.
But what do you propose to do about it either way? Go join Lawrence Lessig's anti-corruption campaign. In the meantime it's not like positive change is impossible, it's just harder than it ought to be.
Because bribing and blackmailing are not the same thing. The first one is unfortunately legal as long as its done the right way (through campaign contributions and PACs) and the second one is still a crime.
Except one leaves the congressperson happy and one leaves the congressperson angry. Do you think the angry or the happy person is most likely to anonymously disclose this information to a journalist?
So they'd spy on everyone, throw whistleblowers in jail, pass naked selfies of citizens around and more, but they'd never try to blackmail politicians or others.
But what do you propose to do about it either way? Go join Lawrence Lessig's anti-corruption campaign. In the meantime it's not like positive change is impossible, it's just harder than it ought to be.