WASHINGTON – The U.S. Supreme Court yesterday limited the ability of people to combine forces and fight corporations together when they want to dispute contracts for cell phones, cable TV and other services, a move consumer advocates called a crushing blow.

A 5-4 majority, led by Justice Antonin Scalia, held that the Federal Arbitration Act trumps a California rule invalidating as “unconscionable” a class action waiver provision in a cell phone arbitration agreement.