Ds were in the business of making bathroom pottery and together controlled 82 percent of all the business in the United States. Ds made an agreement to fix the prices of their products. P brought an action for violation of the Sherman Act. The trial court charged that if it found the agreements or combination complained of, it might return a verdict of guilty without regard to the reasonableness of the prices fixed, or the good intentions of the combining units, whether prices were actually lowered or raised or whether sales were restricted to the special jobbers, since both agreements of themselves were unreasonable restraints. The trial court refused various requests to charge that both the agreement to fix prices and the agreement to limit sales to a particular group, if found, did not in themselves constitute violations of law unless it was also found that they unreasonably restrained interstate commerce. Ds were convicted. The Appeals Court held that the trial court erred in refusing to charge as requested and held in effect that the charge as given on this branch of the case was erroneous. The United States sought certiorari.