During the 1930s, National Association for the Advancement of Colored People (NAACP) attorneys Charles H. Houston, William Hastie, James M. Nabrit, Leon Ransom, and Thurgood Marshall charted a legal strategy designed to end segregation in education. They developed a series of legal cases challenging segregation in graduate and professional schools. Houston believed that the battle against segregation had to begin at the highest academic level in order to mitigate fear of race mixing that could create even greater hostility and reluctance on the part of white judges, After establishing a series of favorable legal precedents in higher education, NAACP attorneys planned to launch an all-out attack on the separate-hut-equal doctrine in primary and secondary schools. The strategy proved successful. In four major United States Supreme Court decisions precedents were established that would enable the NAACP to construct a solid legal foundation upon which the Brown case could rest: Missouri ex rel. Gaines v. Canada, Registrar of the University of Missouri (1938); Sipuel v. Board of Regents of the University of Oklahoma (1948); McLaurin v. Oklahoma State Regents for Higher Education (1950); and Sweatt v. Painter (1950). In the Oklahoma case, the Supreme Court held that the plaintiff was entitled to enroll in the University. The Oklahoma Regents responded by separating black and white students in cafeterias and classrooms. The 1950 McLaurin decision ruled that such internal separation was unconstitutional. In the Sweatt ruling, delivered on the same day, the Supreme Court held that the maintenance of separate law schools for whites and blacks was unconstitutional. A year after Herman Sweatt entered the University of Texas law school, desegregation cases were filed in the states of Kansas, South Carolina, Virginia, and Delaware and in the District of Columbia asking the courts to apply the qualitative test of the Sweatt case to the elementary and secondary schools and to declare the separate-but-equal doctrine invalid in the area of public education. The 1954 Brown v. Board of Education decision declared that a classification based solely on race violated the 14th Amendment to the United States Constitution. The decision reversed the 1896 Plessy v. Ferguson ruling, which had established the separate-but-equal doctrine. The Brown decision more than any other case launched the "equalitarian revolution" in American jurisprudence and signaled the emerging primacy of equality as a guide to constitutional decisions; nevertheless, the decision did not end state sanctioned segregation. Indeed, the second Brown decision, known as Brown II and delivered a year later, played a decisive role in limiting the effectiveness and impact of the 1954 case by providing southern states with the opportunity to delay the implementation of desegregation.