Cohen called on Congress to pass the , introduced in January by Senator Herb Kohl, a Wisconsin Democrat and former president of the Kohl's retail chain. The bill would outlaw vertical price-fixing in U.S. antitrust law.

But vertical price-fixing may have some benefits, and courts should not view such agreements as automatic antitrust violations without considering these benefits, said James Wilson, a partner in the Vorys, Sater, Seymour and Pease law firm and chairman of the American Bar Association's antitrust law section.

Manufacturer RPM policies can allow main-street retailers to compete with big-box discount chains by setting the price both types of stores can charge, Wilson said. A longtime rule against vertical price-fixing "has had the effect of enhancing the market power of very large-scale retailers that carry a wide variety of products," he said. "It has harmed smaller retailers who try to compete with those large retailers not on price ... but on the basis of quality and service."

The legislation may not have a huge impact, Wilson added, because manufacturers could still choose which retailers they do business with. Manufacturers can set prices by avoiding discount retailers, he said.

But Kohl and other senators said they've seen evidence of vertical price-fixing on products such as electronics and toys, even as many U.S. families have less money to spend. "For a lot of my constituents, every penny counts," said Senator Amy Klobuchar, a Minnesota Democrat. "Prices to the American consumers have indeed been elevated."