In the 1938 case Missouri ex rel. Gaines v. Canada, Lloyd Gaines, a black student, was denied admission to the University of Missouri's law school solely based on his race. The state offered to pay for his tuition at an out-of-state law school instead as part of its policy of "separate but equal" education under Plessy v. Ferguson (1896). However, Gaines sued and took his case all the way up to the Supreme Court arguing that this arrangement still violated his Fourteenth Amendment rights by denying him equal protection under the laws. The U.S Supreme Court ruled in favor of Gaines in a 6-2 decision stating that while states can provide separate facilities for different races they must exist within their borders; it is not enough just to offer payment for attending similar institutions elsewhere. This ruling marked an important step towards ending segregation as it challenged and began chipping away at the established doctrine of "separate but equal".

In the dissenting opinion for Missouri ex rel. Gaines v. Canada, Justice James Clark McReynolds argued that the majority's decision was a departure from established legal principles and precedent regarding state sovereignty in education policy. He contended that states have broad discretion to regulate their own educational systems, including establishing separate schools for different races if they provide substantially equal facilities and opportunities. In his view, Missouri had met this standard by offering to pay for Gaines' tuition at an out-of-state law school since it did not have a separate law school for black students within its borders at the time. Therefore, he believed there was no violation of Gaines' constitutional rights under the Fourteenth Amendment's Equal Protection Clause as interpreted by previous Supreme Court decisions such as Plessy v. Ferguson (1896). McReynolds also expressed concern about potential unintended consequences of forcing states to integrate their schools or establish duplicate institutions based on race.