III. The Courts Began to Undermine Jim Crow

Before the Supreme Court decided Brown v. Board of Education, civil rights lawyers had already begun to weaken the legal structure of Jim Crow. They did not yet have a Court willing to declare segregation unconstitutional across public education. So they attacked the system piece by piece. They exposed contradictions. They forced states to defend inequality in concrete terms. They made the courts confront the daily machinery of racial hierarchy.

This legal strategy mattered because Jim Crow depended on a lie. The lie was that separation could be equal. Civil rights lawyers understood that the claim was false, but they also understood that courts often moved slowly. The attack, therefore, had to be disciplined. It had to build a record. It had to show that segregation was not merely separation, but a system of enforced inferiority.

One early blow came in voting. In Smith v. Allwright, decided in 1944, the Supreme Court struck down the Texas White primary. The case came just before the formal beginning of this period, but it shaped the postwar struggle. The White primary had allowed political parties to exclude Black voters from the only election that often mattered in one-party Southern states. By striking it down, the Court opened a legal door. But the decision did not end disfranchisement. White officials still used poll taxes, literacy tests, intimidation, purges, and violence. The case showed both the importance and the limits of court victories. Law could remove one barrier while leaving the structure of exclusion largely intact.

Transportation was another battlefield. In Morgan v. Virginia, decided in 1946, the Supreme Court ruled that Virginia could not enforce segregated seating on interstate buses because it burdened interstate commerce. The decision did not declare all bus segregation unconstitutional. It did not protect every Black traveler from harassment or arrest. But it gave civil rights activists a legal tool. It helped set the stage for later direct-action challenges, including the Freedom Rides. The law had begun to crack, but only organized people could force the crack open.

Housing segregation also came before the Court. In Shelley v. Kraemer, decided in 1948, the Supreme Court addressed racially restrictive covenants. These covenants were private agreements that barred Black people and other disfavored groups from buying or occupying homes in certain neighborhoods. The Court did not say that private racism had disappeared. It did not say that White homeowners could not hold racist views. What it said was more limited but still important: courts could not enforce those private racial covenants without violating the Fourteenth Amendment.

Shelley mattered because it exposed how private discrimination often depended on public power. White homeowners, real estate agents, banks, and neighborhood associations could claim that segregation was private choice. But when they went to court to enforce racial exclusion, the state became part of the discrimination. The decision weakened one legal tool of housing segregation. It did not end redlining, racial steering, violence, exclusionary zoning, or discriminatory lending. Still, it made clear that the Constitution could reach racial hierarchy when private arrangements were backed by the courts.

The campaign against segregation in graduate and professional education became especially important. In Sipuel v. Board of Regents of the University of Oklahoma, decided in 1948, the Supreme Court held that Oklahoma had to provide legal education to a Black applicant on the same basis as it provided it to White students. The state could not simply deny her access and offer vague promises of future equality. The decision forced states to confront the cost and absurdity of maintaining separate graduate programs.

Two 1950 cases pushed the point further. In Sweatt v. Painter, the Supreme Court considered Texas’s attempt to create a separate law school for Black students rather than admit Heman Sweatt to the University of Texas School of Law. The Court recognized that equality could not be measured only by buildings, books, and faculty numbers. Reputation, alumni networks, professional standing, and access to the legal community mattered. These “intangible” factors made the separate Black law school unequal.

That same year, in McLaurin v. Oklahoma State Regents, the Court confronted another form of humiliation. Oklahoma had admitted George McLaurin, a Black graduate student, but forced him to sit apart from White students in classrooms, the library, and the cafeteria. The Court ruled that this treatment impaired his ability to study, learn, and exchange ideas. In plain terms, the state could not admit a Black student and then build a cage around him inside the institution. Segregation was not a neutral arrangement. It damaged education itself.

These cases did not yet overrule Plessy v. Ferguson. They worked around it, narrowed it, and exposed its weakness. The Court was beginning to admit what Black communities had always known: separation carried stigma, denied opportunity, and protected White status. Each case made it harder for states to pretend that segregated education was equal.

The legal challenge to racial hierarchy was not limited to Black and White segregation. In California, Mexican American families challenged school segregation in Mendez v. Westminster. Decided in 1947 by the federal courts, the case struck down the segregation of Mexican American children in several Orange County school districts. Mendez mattered because it showed that school segregation reached beyond the formal Black-White lines of Southern Jim Crow. It also helped develop arguments that would later shape the attack on segregated public education more broadly.

Other cases showed that the courts were beginning, unevenly, to recognize racial discrimination against groups not always treated in law as Black. In Hernandez v. Texas, decided in 1954, the Supreme Court held that Mexican Americans could be a distinct class protected by the Equal Protection Clause when excluded from juries. That case belongs more fully in the story of Latino legal struggle, but it is important to mention here because it exposed a central feature of racial hierarchy: law could shift racial categories when convenient, but communities still experienced organized exclusion.

Asian American communities also challenged the legal remnants of exclusion. Cases involving Japanese immigrants and their families weakened alien land laws and other state efforts to mark Asian people as permanent outsiders. These decisions did not erase the damage caused by exclusion, incarceration, and racial suspicion. But they showed that the courts were beginning to confront some of the legal architecture that had placed Asian immigrants and Asian Americans outside full belonging.

The courtroom victories of this period were important, but they were not enough. Courts could issue decisions. They could not, by themselves, make local officials obey. They could not guarantee safe schools, fair housing, equal medical treatment, or voting rights. They could not stop White employers, sheriffs, registrars, landlords, and school boards from finding new ways to preserve old power. The law was beginning to move, but racial hierarchy was moving too.

That is why these cases should not be remembered as a simple march of progress. They were part of a struggle. Civil rights lawyers, families, students, veterans, churches, and local organizations pushed the courts to act. The courts began to undermine Jim Crow because people forced the contradiction into public view. By the early 1950s, the legal foundation of segregation was weaker than it had been in 1945. But it had not collapsed. That collapse would require Brown, and even Brown would not be enough without mass resistance to racial hierarchy in everyday life.