Dean Milk Co. v. City of Madison, Wisconsin

Madison's (defendant) ordinance barred selling pasteurized milk unless it was processed at a plant within five miles of the city; Dean Milk (plaintiff), pasteurizing at plants 65 and 85 miles away in Illinois, was effectively excluded from the Madison market and sued, arguing the ordinance violated the Commerce Clause and Fourteenth Amendment. The lower courts upheld the ordinance, and Dean Milk appealed to the Supreme Court.