By 1901, the United Hatters Union of North America (UHU) (codefendant) had organized 70 of the 82 hat manufacturers in North America. The union had about 900 members in local unions and was affiliated with the American Federation of Labor. But Danbury, Connecticut, hat manufacturer D. E. Loewe & Company (the Danbury Hatter) (plaintiff) refused to recognize the union and did not require its employees to be members. With the labor federation’s assistance, UHU called for a strike at the Danbury factories and boycotted the hats they produced. Specifically, UHU boycotted any wholesalers and dealers that sold Danbury hats, even if they also sold hats made by other manufacturers. The Danbury Hatter sued the union and its representative Martin Lawlor (codefendant) in federal court under the Sherman Antitrust Act, alleging the boycott amounted to an illegal restraint of interstate commerce. The trial court found that the boycott was not actionable as a federal antitrust violation and dismissed the case. On appeal, the circuit court certified the question of whether the Danbury Hatter had stated a cognizable claim under the Sherman Act for the Supreme Court to decide.