The U.S. Supreme Court case Atlantic Coast Line Railroad Co. v. Florida in 1934 revolved around a dispute between the railroad company and the state of Florida regarding taxation on railway properties. The State Tax Assessor had assessed taxes based on an increased valuation of the railroad's property, which was significantly higher than previous years' assessments and disproportionately high compared to other commercial properties in the state. The Atlantic Coast Line Railroad Company argued that this assessment violated their rights under both federal law and the Fourteenth Amendment by denying them equal protection under law due to discriminatory taxation practices. The Supreme Court ruled in favor of Atlantic Coast Line Railroad Co., finding that there was indeed discrimination against interstate commerce as well as a violation of equal protection rights because similar intrastate businesses were not subjected to such high tax rates or valuations for their properties.

In the dissenting opinion for Atlantic Coast Line Railroad Co. v. Florida, Justice Stone argued that the majority's decision to uphold a state law requiring railroads to maintain separate but equal facilities for black and white passengers was inconsistent with previous Supreme Court rulings on interstate commerce. He contended that this ruling effectively allowed states to regulate interstate trains, which should fall under federal jurisdiction according to the Commerce Clause of the Constitution. Furthermore, he pointed out that maintaining separate facilities often meant providing inferior services for black passengers, thereby violating their constitutional rights under the Fourteenth Amendment's Equal Protection Clause. Therefore, in his view, both from an interpretation of federal powers over interstate commerce and protection of individual civil rights perspectives, such laws should be struck down as unconstitutional.