Tampa Electric Company (Tampa Electric) (plaintiff) was a public utility company that provided electricity in and around Tampa Bay, Florida. In May 1955, Tampa Electric entered into an agreement with Nashville Coal Company (Nashville Coal) (defendant), a producer of coal, which obligated Tampa Electric to buy from Nashville Coal all of Tampa Electric’s coal needs for two units of a new electric plant for a period of 20 years. The exclusive-dealing arrangement also provided that Tampa Electric would purchase at least 225,000 tons of coal per year for the duration of the contract. Before any coal was delivered, Nashville Coal repudiated the contract, claiming that it was illegal under the antitrust laws. Tampa Electric sought a declaratory judgment that the exclusive-dealing arrangement was valid and enforceable. Nashville Coal countered that the arrangement was unlawful under §§ 1 and 2 of the Sherman Act and § 3 of the Clayton Act, and thus unenforceable. The district court and court of appeals held in favor of Nashville Coal, finding the agreement to violate § 3 of the Clayton Act. Tampa Electric appealed.