WASHINGTON, D.C. - The United States told the U.S. Supreme Court on Jan. 29 in an amicus curiae brief that the Second Circuit U.S. Court of Appeals properly ruled that a mandatory class action waiver clause in American Express Co.'s (AmEx) standardized service contract violated the Federal Arbitration Act (FAA) because it prevented merchants from effectively vindicating their antitrust claims in any forum (American Express Company, et al. v. Italian Colors Restaurant, et al., No. 12-133, U.S. Sup.).