Racial segregation was codified into law in the South. In the North, it was a de facto way of life. This means that there was frequent discrimination in employment and housing in Northern states that non-white people, particularly black people, often did not have the legal resources to contest. However, the legal system of segregation, known as Jim Crow, did not exactly expand. The Supreme Court ruling in Plessy v. Ferguson (1896) sanctioned "separate but equal" public facilities, rolling back Reconstruction era attempts to integrate black people more fully into Southern society.
The National Association for the Advancement of Colored People (NAACP) brought cases before the Supreme Court that challenged legal segregation. The most significant progress was made in education and it was this progress which allowed for the full desegregation of public facilities. Initially, the NAACP's legal wing challenged segregation at universities, particularly law schools. Later, it would challenge segregation in public schools. Brown v. Board of Education of Topeka, Kansas (1954) was a key Supreme Court decision that rolled back the language of Plessy, declaring that separate meant unequal and, therefore, violated the equal protection clause of the Fourteenth Amendment.
In the following year, the Supreme Court released a second decision related to Brown which was to direct Southern states to desegregate their schools "with all deliberate speed." Despite this directive from the Court that Southern states and school districts proceed to obey the law and carry it out, the first Southern school, Little Rock High School, was not desegregated until September 1957. Therefore, the Supreme Court did not respond to an expansion of racial desegregation. Instead, it merely sought to reverse a decision that was later found to be unconstitutional.