In his solo dissent, Justice John Marshall Harlan argued strongly against the majority’s decision upholding the Separate Car Act. Harlan asserted that railroads act as public highways and exercise public functions, meaning that state legislatures can’t regulate their use based solely on race. He wrote that “[i]n respect of civil rights, common to all citizens, the Constitution of the United States does not, I think, permit any public authority to know the race of those entitled to be protected in the enjoyment of such rights. Every true man has pride of race, and under appropriate circumstances when the rights of others, his equals before the law, are not to be affected, it is his privilege to express such pride and to take such action based upon it as to him seems proper. But I deny that any legislative body or judicial tribunal may have regard to the race of citizens when the civil rights of those citizens are involved.”

Harlan found that the intent of the Separate Car Act was obviously to harm Black Americans, arguing that “[e]very one knows that the statute in question had its origin in the purpose, not so much to exclude white persons from railroad cars occupied by blacks, as to exclude colored people from coaches occupied by or assigned to white persons.” The result of the Court’s decision to uphold the law was the infringement of personal liberty for millions of Americans. Harlan wrote, “If a white man and a black man choose to occupy the same public conveyance on a public highway, it is their right to do so, and no government, proceeding alone on grounds of race, can prevent it without infringing the personal liberty of each.”

In the view of the Thirteenth Amendment, Harlan found that “[t]he arbitrary separation of citizens, on the basis of race, while they are on a public highway, is a badge of servitude wholly inconsistent with the civil freedom and the equality before the law established by the Constitution. It cannot be justified upon any legal grounds.” He argued that such a system of laws went against America’s promise of freedom.

Harlan concluded warning that “[i]f evils will result from the commingling of the two races upon public highways established for the benefit of all, they will be infinitely less than those that will surely come from state legislation regulating the enjoyment of civil rights upon the basis of race. We boast of the freedom enjoyed by our people above all other peoples. But it is difficult to reconcile that boast with a state of the law which, practically, puts the brand of servitude and degradation upon a large class of our fellow-citizens, our equals before the law. The thin disguise of “equal” accommodations for passengers in railroad coaches will not mislead anyone, nor atone for the wrong this day done.”