In the United States Supreme Court case of United Gas Pipe Line Co. v. Mobile Gas Service Corp., the court ruled on a dispute between a gas supplier and its customer regarding changes in contract rates for natural gas supply. The supplier, United Gas Pipe Line Company, sought to unilaterally change the rate it charged under an existing contract with Mobile Gas Service Corporation by filing new tariff schedules with Federal Power Commission (FPC). However, Mobile contested this action arguing that such unilateral changes violated their contractual agreement and were not permissible under Section 4 of Natural Gas Act which governs rate modifications. The Supreme Court sided with Mobile ruling that while suppliers can propose rate changes to FPC as per section 4(d) of Natural Gas Act, they cannot unilaterally alter agreed-upon contractual rates without consent from customers or approval from FPC after due hearing process as required by law.

In the dissenting opinion for United Gas Pipe Line Co. v. Mobile Gas Service Corp., Justice Reed argued that the Federal Power Commission (FPC) should not have jurisdiction over contract rates between natural gas companies and their customers unless there is a clear violation of public interest or an issue with unjust or unreasonable rates. He believed that Congress intended to protect private contracts from unnecessary government interference when it enacted the Natural Gas Act, which only allows FPC intervention in cases where existing contractual arrangements are detrimental to public interests. The majority's decision, according to him, would undermine this principle by allowing regulatory authorities too much power over private agreements without sufficient cause.