In the aftermath of Reconstruction, which ended in 1877, the Southern State governments again became—as they remained in the North—“white man's governments.” The new State legislatures enacted Jim Crow laws to legally segregate the races and impose second-class citizenship upon African Americans. Enforced by criminal penalties, these laws created separate schools, parks, waiting rooms, and other segregated public accommodations. In its ruling in the Civil Rights Cases of 1883, the Court made clear that the Equal Protection Clause of the 14th Amendment provided no guarantee against private segregation. It would now be asked to rule on what protection the 14th Amendment offered in matters of public segregation.

In 1890, the Louisiana legislature passed a law requiring railroads to separate passengers on the basis of race. Trains that had two or more passenger cars were required to have designated seating for different races. If there was only one passenger car in a train, these cars were to be divided by a curtain or some other form of partition. A State fine of $25 or up to 20 days in jail was the penalty for sitting in the wrong compartment.

Timidity in the protection of individual rights—as reflected in the Civil Rights Cases decision—was a dominant characteristic of the late 19th-century Court. Attacks on its authority after the infamous Dred Scott decision in 1857 still plagued the bench and reinforced its regressive tendencies.

Homer Adolph Plessy was a successful Louisiana businessman living in Baton Rouge. Comfortable in the society of both racial groups, Plessy had had one African-American grandparent. Although he did not consider himself African American, Louisiana law defined him as “octaroon”—one-eighth African American.

Plessy, acting on behalf of a committee that had been formed to challenge Jim Crow laws, intentionally broke the law in order to initiate a case. Returning by rail from New Orleans to Baton Rouge, Plessy was asked by railroad officials to sit in the segregated area of the train. He refused. Arrested and charged, Plessy petitioned the Louisiana Supreme Court for a writ against Ferguson, the trial court judge, to stop the proceedings against him for criminal violation of the State law. But the Louisiana State Supreme Court refused. Convicted and fined, Plessy then appealed to the Supreme Court of the United States.

The arguments in the case revolved around the 13th Amendment and the Equal Protection Clause of the 14th Amendment. Did the Louisiana law requiring segregated seating violate Plessy's “equal protection” under the law? Was a State law requiring separate accommodations on a public conveyance for whites and African Americans a violation of equal protection? Should the State law be ruled unconstitutional and Plessy's conviction overturned? Or would “separate but equal” facilities meet the standard of the 14th Amendment?

For Plessy: Segregated facilities violate the Equal Protection Clause. As a fully participating citizen, Plessy should not have been denied any rights of citizenship. He should not have been required to give up any public right or access. The Louisiana law violated the Equal Protection Clause and was, therefore, unconstitutional.

For the State of Louisiana: It is the right of each State to make rules to protect public safety. Segregated facilities reflected the public will in Louisiana. A separate but equal facility provided the protections required by the 14th Amendment and satisfied the demands of white citizens as well. If the Civil Rights Cases of 1883 made clear that segregation in private matters is of no concern to government, why should a State legislature be prohibited from enacting public segregation statutes?

Justice Henry B. Brown of Michigan delivered the 7-1 decision of the Court that upheld the Louisiana law requiring segregation. Brown noted that the law did not violate either the 13th or 14th Amendments. He stated that the 13th Amendment applied only to slavery, and the 14th amendment was not intended to give African Americans social equality but only political and civil equality with white people.

Using a line of reasoning that would echo across the next 60 years of political debate and Court opinion, Brown wrote that “Legislation is powerless to eradicate racial instincts or to abolish distinctions based upon physical differences….” In other words, legislation cannot change public attitudes, “and the attempt to do so can only result in accentuating the difficulties of the present situation,” Brown wrote. Reflecting the common bias of the majority of the country at the time, Brown argued that “If the civil and political rights of both races be equal, one cannot be inferior to the other civilly or politically. If one race be inferior to the other socially, the Constitution of the United States cannot put them upon the same plane.” The Court declared the Louisiana law a reasonable exercise of the State's “police power,” enacted for the promotion of the public good.

In the key passage of the opinion, the Court stated that segregation was legal and constitutional as long as “facilities were equal.” Thus the “separate but equal doctrine” that would keep America divided along racial lines for over half a century longer came into being.

Somewhat ironically, while Brown, a Northerner, justified the segregation of the races, Justice John Marshall Harlan, a Southerner from Kentucky, made a lone, resounding, and prophetic dissent. “The Thirteenth Amendment…struck down the institution of slavery [and]…decreed universal civil freedom,” Harlan declared. “Our Constitution is color-blind and neither knows nor tolerates classes among citizens.” Harlan's dissent became the main theme of the unanimous decision of the Court in Brown v. Board of Education in 1954.

No great national protest followed in the wake of the Plessy decision. Segregation was an issue shunted off to the corner of our national life, and would remain so for nearly 60 years.