Comment by Nevermark

Except for clusters of highly correlated private interest groups. PACs. Which completely circumvent that.

Ideally they "shouldn't". But in practice they do.

Because the Supreme Court determined that money is free speech, its use in elections cannot be limited in general.

And where coordination between purportedly independent groups isn't supposed to happen, there is a strong "don't ask, don't tell" code, and a mountain of lawyers ready to scream "political oppression!" on the dime of the rich.