New evidence of the clout of veteran U.S. Supreme Court advocates and their law firms is revealed in a study showing that the language in their briefs appears in court opinions more often than that of newcomers to the court.

Covington & Burling and O’Melveny & Myers, as well as individual advocates including Sidley Austin’s Carter Phillips and Chief Justice John Roberts Jr., a former appellate litigation partner, are at the top of lists in the study, which shows language overlap between briefs and decisions.