Here’s a wonderful article by Lawrence Lessig from a while back on the Citizens United Supreme Court case, which prohibited congress from regulating independent campaign expenditures by corporations:
This is linked off of rootstrikers.org, but I hadn’t read it in detail before. His core argument is great: in key places in their decisions, the justices made statements such as
The appearance of influence or access . . . will not cause the electorate to lose faith in our democracy.