The case of Swift & Co., Inc. v. Wickham, Commissioner of Agriculture & Markets of New York in 1965 revolved around the constitutionality of a New York law that regulated the labeling and grading standards for meat products sold within its borders. The plaintiffs, including Swift & Co., were out-of-state meat packers who argued that this state law was preempted by federal legislation - namely, the Federal Wholesome Meat Act - and thus violated the Supremacy Clause of the U.S Constitution. However, upon review, it was determined by a majority decision from Justice Hugo Black's court that there was no conflict between state and federal laws as they had different scopes; while federal law aimed to ensure wholesomeness (safety) in meats shipped interstate commerce or imported from foreign countries into states with less stringent regulations than those set forth by Congress itself; on other hand NY’s statute focused solely on quality grades for consumer information purposes only within its own jurisdictional boundaries without any impact whatsoever over interstates trade flows nor international imports under Congressional purview.

In the dissenting opinion for Swift & Co., Inc. v. Wickham, Justice Harlan argued that the majority's decision was an unnecessary expansion of federal jurisdiction over state laws and a departure from established principles of federalism. He contended that there was no need to invoke the Supremacy Clause in this case because it did not involve a direct conflict between state and federal law but rather dealt with two separate regulatory schemes operating within their respective spheres of authority. Furthermore, he criticized the majority's reliance on preemption doctrine as inconsistent with previous rulings which had upheld concurrent state regulation even where some overlap existed with federal law. In his view, such coexistence should be tolerated unless Congress explicitly intended to displace all related state legislation or if compliance with both sets of regulations would be physically impossible.