G.S. Suppiger Co. (Suppiger) (plaintiff) held a patent for a machine that deposited salt tablets into cans during the canning process. Suppiger also owned a subsidiary that manufactured salt tablets for use in Suppiger’s machines, but these salt tablets were unpatented. Suppiger leased over 200 of its salt deposition machines to commercial canneries using a license agreement. The license agreement’s terms forced the canneries to use Suppiger’s unpatented salt tablets in Suppiger’s patented machines. In other words, Suppiger tied the use of its machines to the use of its tablets. This type of arrangement is sometimes referred to as a tying arrangement. Morton Salt Co. (Morton) (defendant) also manufactured machines for depositing salt tablets, but Morton’s machines were unpatented. Suppiger sued Morton, alleging infringement of the patent for Suppiger’s salt-depositing machines and seeking an injunction against Morton. Morton moved for summary judgment. The trial court granted Morton’s motion and dismissed Suppiger’s complaint. The trial court found that Suppiger was misusing its patent to restrain the sale of salt tablets by competitors. Thus, if the trial court enforced Suppiger’s patent, the trial court would be helping enforce an unlawful monopoly. Therefore, the trial court could not enforce the patent. The Court of Appeals for the Seventh Circuit reversed. The Supreme Court granted certiorari.