Tim Lee has written an excellent post on the confusion at the heart of Stephen Colbert’s ColbertPAC:

In progressive mythology, Citizens United is a case about whether large corporations like BP, Verizon, and Pfizer can use their vast resources to buy ads that drown out the voices of other participants in the political debate and sway elections toward candidates they favor. This is a real problem, and I think Senators McCain and Feingold sincerely believed the legislation that bears their names would help solve it.
But “corporations” include many entities beyond the Fortune 500. The ACLU, Sierra Club, and Human Rights Watch are all corporations. “Free speech for corporations” might sound insidious if the corporation in question is Exxon Mobil. But it’s harder to get worked up about the corrupting influence of “corporate speech” when we’re talking about the ACLU running television ads criticizing a candidate for supporting the Patriot Act.

As Tim goes on to explain, seems to have missed the point of his own gag:

Stephen Colbert is trying (or at least pretending) to create a vehicle for his fans to pool their money so that Colbert can create ads “promoting” (mocking) conservative candidates. The ads are guaranteed to be funny, and they could also influence 2012 political races. I think that’s a brilliant idea, and I’m glad that the Supreme Court has affirmed Colbert’s (and his fans’) right to engage in this type of political speech. Colbert, in contrast, seems to be mocking his own free of speech rights. By asking us to root against Colbert-the-character’s quest for a PAC, Colbert-the-comedian seems to be implying that it’s ridiculous that the law would allow him to create such a PAC. But it isn’t ridiculous. Colbert should be free to create the PAC, people should be free to give to it, and Colbert should be free to tell people about the PAC on his show.

I recommend reading Tim’s post, which gave me a much clearer picture of the issues at stake.