The Supreme Court unanimously ruled in favor of Dean Milk Co., finding that the Madison ordinance violated the dormant Commerce Clause of the U.S.

Constitution.

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The Court held that the 5-mile radius requirement for milk pasteurization plants discriminated against out-of-state producers and was not the least restrictive means to achieve the city's public health objectives.

This case established the precedent that local regulations which discriminate against out-of-state commerce are subject to strict scrutiny under the dormant Commerce Clause.

The Court rejected Madison's argument that the 5-mile limit was necessary to ensure prompt delivery of fresh milk, finding that this interest could be achieved through less discriminatory means.

The ruling was seen as an important victory for the free flow of interstate commerce, limiting the ability of local governments to erect barriers against out-of-state businesses.

The case highlighted the tension between state/local powers and federal oversight of interstate commerce under the Constitution.

Dean Milk Co.

was able to continue selling its milk in Madison after the ruling, expanding market access for an out-of-state producer.

The decision was praised by industry groups who saw it as protecting small and medium-sized businesses from unfair local regulations.

Some public health experts criticized the ruling, arguing that it compromised local governments' ability to ensure food safety standards.

The case sparked debate about the appropriate balance between economic and public health/safety concerns in Commerce Clause jurisprudence.

The precedent set in Dean Milk Co.

has been cited in numerous subsequent Supreme Court decisions related to the dormant Commerce Clause.

The ruling demonstrated the Court's willingness to apply a strict scrutiny test to local laws that burden interstate commerce, even when public health is cited as the rationale.