Justice Ruth Bader Ginsburg has missed a month of Supreme Court arguments as she recovers from lung cancer surgery. But she’s not the first justice to be away for a while and her absence hardly compares with those of some of her predecessors.

The day before the Supreme Court began its term in October 1949, Justice William Douglas broke 14 ribs and suffered a punctured lung when he was thrown from his horse on a trail in the Cascade Mountains in Washington.

He didn’t return to the bench for nearly a half year, and his long recovery caused delays in several cases, including challenges to segregation.Like much of what goes on away from public view at the Supreme Court, how the justices deal with a colleague’s absence can be opaque. The individual justice decides whether to rule on cases even if she has missed arguments. Indeed, Chief Justice John Roberts already has announced that Ginsburg is participating in the cases she missed.

And only the justice can decide when an injury or illness is so severe that retirement is the only option. A quarter century after his riding accident, Douglas suffered a serious stroke, but refused to retire for months. His weakened state caused a backlog in the court’s work and the other justices refused to issues decisions in cases where Douglas had provided the fifth, majority-making vote.

“There aren’t any rules about this and so much is left to the individual justice,” said Erwin Chemerinsky, who argued a case during Ginsburg’s absence.

The 85-year-old Ginsburg could be back on the bench when the court next meets on Tuesday, and even as she has been away, she has not missed any votes.

In some state court systems, including California, the highest court can essentially borrow a judge from a lower court to temporarily replace an absent member, said Chemerinsky, the dean of the law school at the University of California, Berkeley.
The Supreme Court has no similar arrangement.

The nine justices are there for as long as they wish, and neither a retired justice nor an appellate judge can fill a void. The 25th Amendment to the Constitution sets out what happens if a president is incapacitated, but refuses to relinquish power.