The plaintiffs in the case K.M.K. v. Washington Interscholastic Activities Association effectively want the Supreme Court to bar trans women from women’s sports teams at high schools and universities. | Heather Diehl/Getty Images One of the last decade’s most consequential changes to how the Supreme Court operates is the growth of the so-called shadow docket — a process that allows the justices to decide cases unusually quickly, and often without full briefing or oral argument. Historically, the Court would typically allow contentious legal issues to percolate in the lower courts for...