A loss before the U.S. Supreme Court has led to an unusual legal malpractice suit against McGuireWoods and one of its New York partners.

Queens-based Ideal Steel Supply Corp. was the losing party in the high court’s ruling last year in Anza v. Ideal Steel, 547 U.S., a decision sharply limiting the ability of third parties to bring civil claims under the Racketeer Influenced and Corrupt Organization Act.