Supreme Court Justice Clarence Thomas was absent from the court on Monday with no explanation.
Mr Thomas, 75, also was not participating remotely in arguments, as justices sometimes do when they are ill or otherwise cannot be there in person.
Chief Justice John Roberts announced Mr Thomas’ absence, saying that his colleague would still participate in the day’s cases, based on the briefs and transcripts of the arguments.
The court sometimes, but not always, says when a justice is out sick.
Mr Thomas was admitted to hospital two years ago with an infection, causing him to miss several court sessions. He took part in the cases then, too.
He is the longest serving of the current justices, joining the Supreme Court in 1991.
