Tuesday was a historic day at the Supreme Court, not just because of the oral argument in the Second Amendment case D.C. v. Heller. It also marked the first time that Oscar the Grouch entered the annals of Supreme Court jurisprudence.

Justice Antonin Scalia is the one to thank for this milestone. He mentioned the famous Sesame Street character in a tart rebuke aimed at Chief Justice John Roberts Jr. The mention was contained in a Scalia dissent filed in the case of Washington State Grange v. Washington State Republican Party, decided Tuesday.In that decision, authored by Justice Clarence Thomas, the Court upheld the “top two” primary system in Washington state, which allows candidates to list on the ballot their party preferences — whether or not the party they prefer wants to be identified with them. The parties complained their First Amendment right not to associate with the candidates would be violated, and voters would be confused.In a concurrence, Roberts supported the majority’s view that voter confusion was not at all certain just because a candidate says, “I prefer the Democratic party.” To illustrate his point, Roberts said that the statement “I like Campbell’s soup” would not necessarily imply any connection with the Campbell Soup Co.Scalia, who argued that parties’ rights were infringed in part because they cannot rebut the candidate’s statement of preference, could not resist. Referring to Roberts’ Campbell’s soup analogy, Scalia said, “It is hard to know how to respond.” Washington’s law, he continued, amounted to allowing “Oscar the Grouch (Sesame Street’s famed bad-taste resident of a garbage can)” to endorse Campbell’s soup repeatedly, without allowing the soup company to disavow his statement. A database check confirms this was the first time Oscar the Grouch has been mentioned in a Supreme Court opinion.Roberts did not address the Oscar the Grouch gambit, except to note drily that Scalia, after writing that he did not know how to respond, “soldiers on nonetheless.”First reported in The BLT: The Blog of Legal Times