The National Retail Federation told the U.S. Supreme Court that the debate over debit card swipe fees is “of staggering importance” and asked the justices to review a ruling that left the Federal Reserve’s cap on the billions of transactions conducted each year at 21 cents rather than reducing it to a lower level. A petition asking the Supreme Court to consider the case was filed today by NRF, the National Association of Convenience Stores, the Food Marketing Institute, the National Restaurant Association, NRF member Boscov’s Department Store, and NACS member Miller Oil Co., all of whom were plaintiffs in the original lawsuit. While lower than the average of 45 cents before the cap was set, NRF argued that the 21-cent figure included costs that went beyond those allowed under the legislation and filed suit against the Fed in U.S. District Court in 2011 along with other retail groups. The U.S. Court of Appeals for the District of Columbia overturned Leon’s ruling, citing “ambiguity” in the 2010 law and saying the Fed based the cap on a “reasonable interpretation” of the measure.