SAN FRANCISCO — When President-elect Donald Trump takes office later this month, he’ll be greeted by four vacancies at the U.S. Court of Appeals for the Ninth Circuit—the nation’s largest circuit court and, by reputation, one of its most liberal.

The prospect of four Republican appointees joining the court prompted the conservative news site breitbart.com to proclaim in a recent headline: “Liberals Panic as Trump Could Flip Left-Leaning Ninth Circuit.”