The U.S. Supreme Court case Federal Power Commission v. United Gas Pipe Line Co., et al., 1966, revolved around the jurisdiction of the Federal Power Commission (FPC) over natural gas companies' sales for resale in interstate commerce under Section 1(b) of the Natural Gas Act. The FPC had issued an order requiring United Gas to keep detailed accounts and records of its direct industrial sales, which was challenged by United as being beyond FPC's authority since these were not "sales for resale". However, the Supreme Court upheld that while section 1(b) does exclude some direct sales from federal regulation, it doesn't completely remove them from all aspects of federal control or oversight. Therefore, it ruled in favor of FPC stating that such record-keeping requirements are within their regulatory power as they help ensure effective monitoring and enforcement against potential discriminatory practices.

In the dissenting opinion for Federal Power Commission v. United Gas Pipe Line Co., Justice Harlan argued that the majority's decision to allow the Federal Power Commission (FPC) to regulate natural gas producers' sales prices was a misinterpretation of both legislative intent and precedent. He contended that Congress did not intend for such extensive regulatory power when it passed the Natural Gas Act, as evidenced by its failure to provide explicit statutory authority or guidelines for price regulation at this level. Furthermore, he pointed out inconsistencies between this ruling and previous decisions in which similar attempts by FPC were rejected due to lack of clear congressional mandate. In his view, allowing such broad interpretation could lead to arbitrary and potentially harmful government interference in private business operations without proper legal basis.