Brian makes an excellent observation about the dime-store language of the Supremes' First Amendment decision. It is language that I think public choice theory helps explain. In fact, I don't think you can make sense of what the Court is saying at all without some reference to their relative economic position in Washington.
You see, the Supremes are relative paupers in D.C., condemned to live out their lives on a good—$190,100 a year—but by big time Washington standards, hardly eye-popping paycheck. Worse, they have no prospect of toiling for a few years deciding presidential elections and such, before quitting to hang out a shingle and lobby the living hell out of their replacement. (Retainer negotiable, billable hours not.)
This situation has fairly driven Chief Justice William Rehnquist around the bend, who spends much time trying to convince the world that federal judges are overworked and underpaid. Worse, the POTUS just saw his take bumped to $400K a year while Rehnquist is stuck at $198K and change, and no fat memoirs advance awaits either.
So when the Supremes complain about "big money" in politics I take that to mean money is going to the wrong people, i.e., not them. On these grounds, the correct and honorable thing is recusal from any case which involves the flow of political money into D.C. It simply is not possible for a sitting Supreme Court justice to be a disinterested party in the matter.