The case, Citizens United v. Federal Election Commission had previously been argued on narrower grounds, regarding the classification of an anti-Hillary Clinton feature film as either a work of art or political advertising, but the Roberts Court demanded that the case be reargued, expanding the scope to a number of campaign finance precedents, which it was really eager to take down (John Paul Stevens, who write the minority opinion, complained, "Essentially, five justices were unhappy with the limited nature of the case before us, so they changed the case to give themselves an opportunity to change the law").
Dahlia Lithwick, as usual, gave a great rundown of last fall's oral argument: the liberal justices and Solicitor General Elena Kagan spoke up for a compelling government interest in limiting the speech of corporations, and about the very real distinctions between companies and individuals which make the suppression of corporate speech fundamentally different from the suppression of individual speech; the conservative justices stood up for the inalienable rights of telcom giants. The hearings predicted the opinions, available here, pretty exactly.
"The censorship we now confront is vast in its reach," Justice Kennedy's majority opinion warns, conjuring up images of black-clad apparatchiks carrying rogue CEOs off to the gulag. (Have you noticed how Kennedy always gets to speak for the majority in 5-4 opinions? I hate that smug swing-vote diva.) Disingenuously, he laments the restrictions campaign-finance law puts on doing-just-fine-thanks advocacy groups like the NRA and ACLU, as a way of garnering sympathy for the corporations who are the real beneficiaries of the ruling, because of their disproportionate resources.
By taking the right to speak from some and giving it to others, the Government deprives the disadvantaged person or class of the right to use speech...
Yeah, really standing up for the disenfranchised there, Ken: this case is about preventing artificial amalgamations of specific interests from drowning out all other speech.
Rejecting another argument, about the perniciousness of outsized corporate influence, Kennedy argues that "generic favoritism or influence theory" is an insufficient, undefinable threat, and that in any case, "The appearance of influence or access, furthermore, will not cause the electorate to lose faith in our democracy." No? Really? Voters aren't disillusioned with the appearance of corporate interest in American politics? Seriously?
At the heart of the majority opinion, though, is the dissolution of any distinction between an individual and a corporation:
Distinguishing wealthy individuals from corporations based on the latter's special advantages of e.g., limited liability, does not suffice to allow laws prohibiting speech... All speakers, including individuals and the media, use money amassed from the economic marketplace to fund their speech, and the First Amendment protects the resulting speech.
Justice Stevens's dissenting opinion is quite long, but begins quite pithily:
A majority of our Supreme Court does not find this argument compelling.
The Court did rule 8-1 to uphold disclosure and disclaimer provisions of campaign finance law. Clarence Thomas is the only one on the Supreme Court, apparently, who does not think that the makers of political ads should be obligated to identify themselves. But then Clarence Thomas, as has been discussed here previously, is a fucking monster.