In the Smiley v. Kansas case of 1904, the US Supreme Court ruled in favor of the state of Kansas. The case revolved around a law that required railroad companies to provide separate but equal accommodations for black and white passengers. A man named George Smiley, who was African American, sued a railway company after he was denied access to a first-class carriage because of his race despite having purchased a first-class ticket. He argued that this violated his Fourteenth Amendment rights which guarantee all citizens equal protection under the law. However, the court upheld Kansas's segregation laws on grounds that they did not violate federal constitutional protections as long as facilities were "separate but equal". This ruling reinforced racial segregation by legitimizing 'Jim Crow' laws across many states until such time these were overturned later in history.

In the dissenting opinion for Smiley v. Kansas, it was argued that the majority's decision to uphold a state law requiring railroad companies to provide separate but equal accommodations for black and white passengers violated both the Fourteenth Amendment and Interstate Commerce laws. The dissenting justices believed that this law imposed an undue burden on interstate commerce by forcing railroads operating in multiple states to comply with differing racial segregation laws. They also contended that such segregation inherently resulted in unequal treatment, thus violating the Equal Protection Clause of the Fourteenth Amendment. Furthermore, they asserted that upholding this law would set a dangerous precedent allowing individual states too much power over interstate commerce regulations at potential detriment to national unity and economic efficiency.