In P. F. Petersen Baking Co. et al v Bryan, Governor, et al., 1933, the U.S Supreme Court dealt with a case involving the constitutionality of an Iowa law that regulated the weight and price of bread sold in bakeries within its jurisdiction. The plaintiffs were bakery companies who argued that this law violated their rights under both federal and state constitutions by interfering with their freedom to contract and conduct business as they saw fit without undue governmental interference or regulation. The court ruled against them stating that such regulations were not unconstitutional but rather fell within the scope of a state's police power to protect public health, safety, morals or welfare - which includes preventing frauds on consumers through deceptive practices like selling underweight loaves at standard prices. This decision reinforced states' authority to regulate trade within their borders for consumer protection purposes even if it might interfere somewhat with businesses' operational freedoms; provided such regulations are reasonable and not arbitrary or discriminatory in nature.

In the dissenting opinion for P. F. Petersen Baking Co. et al v Bryan, Governor, et al., Justice McReynolds argued that Nebraska's law regulating the size and weight of bread loaves was unconstitutional because it interfered with interstate commerce in violation of Article I, Section 8 of the U.S Constitution. He contended that this regulation created an undue burden on out-of-state bakers who would have to adjust their production processes to meet Nebraska's specific requirements or risk being excluded from its market entirely. Furthermore, he questioned whether such a law could actually protect consumers as intended given its potential impact on price and quality competition among bakeries.