That said, there are (at least) two different reasons for embracing the principle of free speech. The first is that a healthy democracy requires a vibrant sphere of public political debate. This is an instrumental reason to encourage free speech. The second is that the right to voice your own opinions and convictions is inherent in the dignity of every human being. This is a moral axiom. Corporations may stake a claim to the first justification. Not being human beings, they have no claim to the second. As far as I can tell, the majority opinion in Citizens United cites exclusively the first, instrumental justification for protecting free speech. But that first justification, being instrumental, raises the question of whether certain forms of political communication are in fact likely to contribute to a vibrant sphere of public political debate. It has been my experience that in general, the more a form of political communication costs, the less it contributes to healthy political discourse. The argument that treating a corporation's purchase of millions of dollars of televised attack ads differently from an individual's statement of an opinion in a town-hall debate amounts to discrimination or repression seems to me the product of calculated naivete on the court's part.
I've tended to focus on the court's failure to rule narrowly, as I don't have the legal chops to argue about a corporation's right to free political speech. The problem here, I suppose, is trying to make that distinction of what speech is healthy and what speech is unhealthy. Who decides? It's much easier to make an argument for absolute rights that are applied totally consistently. Shades of gray are much harder to defend.
One also has to be cognizant of the fact that its fairly easy for a large corporation to buy TV ads, but basically impossible for all but the richest individuals to do so. It's not exactly a level playing field. But is that something the court should take into account when ruling on free speech? It makes me a bad wannabe pundit, but I don't know.