The U.S. Supreme Court case Texas Gas Transmission Corp. et al. v. Shell Oil Co., 1959, revolved around a dispute over natural gas contracts between the two parties involved - Texas Gas Transmission Corporation and Shell Oil Company. The main issue was whether or not the Federal Power Commission (FPC) had jurisdiction to regulate these contracts under Section 7 of the Natural Gas Act, which requires FPC approval for any sale of natural gas intended for interstate commerce that will occur in the future as part of an existing contract agreement. Shell argued that their sales were exempt from this regulation because they fell under "direct" sales rather than "indirect" ones covered by Section 7; however, Texas Gas contended otherwise. In its decision, the Supreme Court sided with Texas Gas stating that even though direct sales are generally exempted from FPC's jurisdiction according to previous rulings like Phillips Petroleum Co v Wisconsin (1954), it doesn't mean all such transactions are automatically excluded without considering other factors like public interest considerations and potential impacts on consumers' rights. Therefore, it concluded that FPC does have authority to review and approve such contractual arrangements involving future deliveries if necessary based on specific circumstances surrounding each case despite them being classified as 'direct' sales initially.

In the dissenting opinion for Texas Gas Transmission Corp. v. Shell Oil Co., Justice Brennan disagreed with the majority's interpretation of Section 7(c) of the Natural Gas Act, arguing that it did not require a certificate from Federal Power Commission (FPC) to transport gas already dedicated to interstate commerce. He contended that this section only applied when companies sought to engage in new sales or transportation services, and thus was irrelevant in cases where companies were merely changing their method of delivery for existing customers. Furthermore, he believed that FPC had no authority over changes in transportation arrangements unless they affected rates or service conditions - which was not demonstrated here. Therefore, according to Justice Brennan’s view, Texas Gas should have been allowed to switch its delivery point without obtaining a new certificate from FPC.