Wachtell, Lipton, Rosen & Katz’s nasty battle with Carl Icahn could finally be over.

On Tuesday the firm and two of its partners defeated malpractice claims lodged by a former client now controlled by the corporate raider. U.S. District Judge Richard Sullivan in Manhattan threw out the suit brought by Icahn’s CVR Energy Inc., finding that a ruling for Wachtell in a related state action last year doomed the case under principles of res judicata.