Amicus Briefs

An amicus curiae, Latin for friend of the court, is a person or organization that is not a party to a case but files a brief to help the court decide it. The practice has roots in English law, and Henry Clay filed one of the earliest amicus briefs in the Supreme Court in Green v. Biddle in 1821. Amicus filings grew slowly for more than a century and then expanded rapidly from the 1960s onward, as advocacy groups, businesses, states, and scholars used them to shape major cases.

Today nearly every argued Supreme Court case attracts amicus briefs, and the Court receives roughly a thousand in a typical term, with landmark cases drawing well over a hundred each. Briefs come from the federal government, often through the Solicitor General, states, members of Congress, trade associations, civil rights and religious groups, and academics. Supreme Court Rule 37 governs them, and since January 1, 2023, filers no longer need the parties' consent. Amici must disclose whether a party's lawyer wrote the brief or who paid for it, and the Court sometimes invites a lawyer to argue as amicus to defend a position no party will.

Studies show that Justices cite amicus briefs in a substantial share of opinions, often for factual and historical information, and the Solicitor General's views carry particular weight, especially when the Court invites them. Critics say the flood of briefs, many funded by interest groups whose backers need not be fully disclosed, gives organized interests an outsized voice and can introduce untested factual claims, and bills have been proposed to require more disclosure of funding. Supporters say amicus briefs bring the Court expertise and perspectives beyond those of the parties.