The whole SuperPAC nonsense is just one more unintended consequence of the McCain Feingold campaign finance reform law. Everybody knows the candidates coordinate with these PACs, but we do this little dance to stay within the confines of an absurd law.
It's pretty simple, and conservatives have been saying it for years: Freedom of speech = freedom to donate and spend money on political advocacy. Idiotic laws that try to constrain this simple truth are both unconsitutional and ineffective. Get rid of McCain Feingold, allow anybody to publicly donate as much as they want directly to any candidate they want, and allow the candidate to spend it however they want. Candidates would be held accountable for their ads, and there wouldn't be any "mystery money" because the donations have to be disclosed.