The Trump administration has declined to back Hillary Clinton as she tries to block a rare court order requiring the former high-ranking cabinet official to sit for a deposition in a public-records lawsuit that confronts her email practices during her time as the U.S. secretary of state.

Clinton, represented by a team from Williams & Connolly, and former aide Cheryl Mills last month appealed a Washington trial judge’s order to the U.S. Court of Appeals for the D.C. Circuit. Their case tests the high bar that plaintiffs must hurdle to secure a deposition involving a current or former cabinet secretary. Mills is represented by lawyers from the litigation boutique Wilkinson Walsh.