The Supreme Court’s growing embrace of the virtues of arbitration continued Wednesday with a 5-4 ruling endorsing labor contracts that send age discrimination claims to arbitration rather than to federal courts.

“We hold that a collective-bargaining agreement that clearly and unmistakably requires union members to arbitrate ADEA claims is enforceable as a matter of federal law,” Justice Clarence Thomas wrote in a ruling that may boost arbitration more broadly than just in age-discrimination cases.