The appeals court judges upheld a 1949 law that forbids demonstrations on the grounds of the high court, on the premise that protests at the court’s doorstep might lead to the perception that the justices are swayed by vox populi rather than the dictates of the law.

“Allowing demonstrations directed at the Court, on the Court’s own front terrace, would tend to yield the opposite impression: that of a Court engaged with — and potentially vulnerable to — outside entreaties by the public,” wrote U.S. Circuit Judge Sri Srinivasan, who argued often before the court as a lawyer and is sometimes mentioned as a future ­Supreme Court justice.

On days when controversial cases are argued and decided, the 50-foot-wide sidewalks surrounding the court are filled with chanting, flag-waving, ­bullhorn-toting protesters of all stripes. The Supreme Court itself, in 1983, ruled that these sidewalks — on First Street NE, just across from the Capitol — are open for protests.