In this context, the Court took a formalistic approach, which distinguished between services and commerce, manufacturing and commerce, direct and indirect effects on commerce, and local and national activities. See concurring opinion of Justice Kennedy in "United States v. Lopez". ("One approach the Court used to inquire into the lawfulness of state authority was to draw content-based or subject-matter distinctions, thus defining by semantic or formalistic categories those activities that were commerce and those that were not.") The Dormant Commerce Clause formalisms spilled over into its Article I jurisprudence. While Congress had the power to regulate commerce, it could not regulate manufacturing, which was seen as being entirely local. In "Kidd v. Pearson", , the Court struck a federal law which prohibited the manufacture of liquor for shipment across state lines. Similar decisions were issued with regard to agriculture, mining, oil production, and generation of electricity. In "Swift v. United States", , the Court ruled that the clause covered meatpackers; although their activity was geographically "local", they had an important effect on the "current of commerce", and thus could be regulated under the Commerce Clause. The Court's decision halted price fixing. "Stafford v. Wallace" (1922) upheld a federal law (the Packers and Stockyards Act) regulating the Chicago meatpacking industry, because the industry was part of the interstate commerce of beef from ranchers to dinner tables. The stockyards "are but a throat through which the current commerce flows," Chief Justice Taft wrote, referring to the stockyards as "great national public utilities." As Justice Kennedy wrote: (in a concurring opinion to "United States v. Lopez"), "Though that approach likely would not have survived even if confined to the question of a State's authority to enact legislation, it was not at all propitious when applied to the quite different question of what subjects were within the reach of the national power when Congress chose to exercise it."