The justices tapped a non-former clerk to argue as an amicus in an upcoming case for the first time in over a decade, according to research by Bloomberg Law.

Amy Weil, of Atlanta, was invited by the U.S. Supreme Court May 25 to brief and argue a specific position in an attorneys’ fee dispute in a social security case that will likely be argued next term.

There have only been 51 other such appointments since the practice began in...