In the case of Armour & Company et al. v. City of Dallas et al., 1920, the U.S Supreme Court ruled in favor of the city's right to regulate local business operations for public health and safety reasons. The dispute arose when Armour & Co., a meatpacking company, challenged an ordinance by the City of Dallas that required all slaughterhouses within city limits to be located at a specific site designated by municipal authorities. The company argued this was an unconstitutional interference with interstate commerce and deprived them of their property without due process or equal protection under law. The court upheld the ordinance as a legitimate exercise of police power aimed at protecting public health and welfare, rejecting claims that it violated constitutional rights or unfairly targeted certain businesses. It held that while states cannot directly regulate interstate commerce, they can impose restrictions on local activities related to such trade if necessary for public safety or welfare purposes - even if these indirectly affect interstate transactions.

The dissenting opinion in the case of Armour & Company et al. v. City of Dallas et al., 1920, argued that the city ordinance was not discriminatory or unreasonable and therefore did not violate the Fourteenth Amendment's Equal Protection Clause. The dissenters believed that it was within a municipality's power to regulate businesses for public health and safety reasons, including setting different rules for different types of businesses based on their potential risks or harms. They contended that meatpacking plants like Armour & Co.'s could pose unique dangers due to their size and operations, justifying stricter regulations compared to smaller butcher shops or markets selling meat products directly to consumers. Furthermore, they disagreed with the majority's view about interstate commerce being impeded by local laws; instead asserting such ordinances were part of states' reserved powers under federalism principles unless Congress explicitly preempted them.