Justice Clarence Thomas (Photo: Getty Images)

California's bitter 2008 campaign over same-sex marriage made a cameo appearance in today's U.S. Supreme Court ruling that struck down limits on corporate campaign spending.

Associate Justice Clarence Thomas joined the majority's main opinion. But he broke with his fellow conservatives on one point. In a six-page dissent,  Thomas argued the majority should also have invalidated campaign laws that require donors to disclose their names, addresses, and other personal information.

Why? Thomas pointed to the Proposition 8 campaign and its aftermath as Exhibit A for everything that's wrong with disclosure provisions. He cited complaints from Prop. 8 supporters that California's requirement to disclose donor identities led to widespread harassment.

Thomas concludes: "I cannot endorse a view of the First Amendment that subjects citizens of this Nation to death threats, ruined careers, damaged or defaced property, or pre-emptive and threatening warning letters as the price for engaging in 'core political speech, the "primary object of First Amendment protection."

Here's the link to the full text of today's Supreme Court opinion:  Citizens United v. Federal Election Commission. Note: It's a 183-page PDF; Thomas's dissent is the final six pages.