Second, campaign finance law is of dubious constitutional validity. Its underlying premise is that the kind of speech that is most important to a functioning free society, political speech, should be limited -- and limited at the whim of the last people who should be given that dangerous power, incumbent office holders who have the most to gain from suppressing commentary. We should not tolerate such laws at all. Those who champion them would not endorse, say, a limitation on pornographic expression based on the political class's judgment about how much a citizen should be permitted to buy or sell.
A corollary to that is this: If such laws inhibiting speech are going to be permitted, that should only be done by the people's accountable representatives in Congress, who must be crystal clear about what is being prohibited. Free speech is too critical a right to permit speech prohibitions to be expanded by the extravagant theories of government prosecutors or elastic rulings of politically insulated judges.
The money involved in the Edwards case was not related to traditional campaign expenditures. It was intended to hide an extramarital affair, not amplify the candidate's political platform and positions. If Congress thinks the public wants such outliers captured in the law's sweep, then it can amend the law to make that clear. Nothing less ought to be satisfactory in light of the obvious nexus between campaign contributions and speech, as well as our law's principle of lenity, which dictates that criminal statutes be written plainly enough to put a person or ordinary intelligence on notice about what has been prohibited.