In the 1976 case Jones, Director, Department of Weights and Measures, Riverside County v. Rath Packing Co., the U.S. Supreme Court ruled on a conflict between federal and state regulations regarding meat packaging standards. The California law required that bacon be sold by weight while federal law allowed for sale by both weight and average weight accounting for moisture loss during curing process. The court held that in this instance, the Federal Meat Inspection Act (FMIA) preempted state laws as it was more comprehensive in its regulation of labeling requirements to prevent consumer deception or confusion about product weights. Furthermore, another California requirement mandating frequent inspections of weighing equipment at packing plants was also found to be preempted by FMIA because such inspections were already covered under federal law which had established less burdensome inspection procedures.

In the dissenting opinion for Jones v. Rath Packing Co., Justice William Rehnquist argued that the majority's decision to strike down California's weight labeling law in favor of a federal standard was an overreach of power. He contended that states should have the right to enforce their own laws when they do not conflict with federal regulations, and believed this case did not present such a conflict. The state law required more specific information on labels than what was federally mandated, but it did not contradict or undermine those requirements. Therefore, he saw no reason why both could not coexist without violating the Supremacy Clause of the Constitution. Furthermore, he expressed concern about potential negative effects on consumer protection efforts at state level due to this ruling.