In its 5-4, AT&T Mobility LLC v. Concepcion decision, the Justices said the Federal Arbitration Act of 1925, originally aimed at disputes over maritime and rail shipments, trumps state laws or legal rulings in states that limit arbitration clauses.

But several business lawyers said class-action claims rarely work to the benefit of consumers. "I think this decision will help consumers, not hurt them," said Alan S. Kaplinsky, Chair of Ballard Spahr's Consumer Financial Services Group. "The only people who do well in the class-action suits are the lawyers. The attorneys get millions in fees, and the consumers get a worthless coupon. For them, it's better to go through arbitration."