They are seatmates on the bench, sometimes smiling or chuckling (when not wearing masks) at a shared joke or story. But Justices Elena Kagan and Brett Kavanaugh increasingly check each other like hockey players with sharp-edged words as they disagree on the most contentious issues facing the U.S. Supreme Court.

The court’s famed collegiality may be tested even more this term as hot-button cases involving abortion, guns and religion now await decision.