Until the late 1940s the public education system in Texas for Mexican Americans offered segregated campuses with often minimal facilities and a curriculum frequently limited to vocational training. The 1950 United States census showed that the median educational attainment for persons over twenty-five was 3.5 years for those with Spanish surnames and, by comparison, 10.3 years for other white Americans; about 27 percent of persons over twenty-five with Spanish surnames had received no schooling at all. No substantive legal suit had been initiated since Del Rio ISD vs. Salvatierra (1930), in which Mexican Americans claimed they had been denied use of facilities used by "other white races" in the same school. In 1948 the League of United Latin American Citizens, joined by the American G.I. Forum of Texas, successfully challenged these inequities of the Texas public school system in Delgado vs. Bastrop ISD.
In 1947 the Ninth Circuit Court in California found that separation "within one of the great races" without a specific state law requiring the separation was not permitted; therefore, segregation of Mexican-American children, who were considered Caucasian, was illegal. In Texas, following this ruling, the attorney general, in response to an inquiry by Gustavo C. (Gus) Garcia, a Mexican-American attorney, agreed that segregation of Mexican-American children in the public school system by national origin was unlawful and pedagogically justified only by scientific language tests applied to all students. On June 15, 1948, LULAC (with Garcia as attorney) filed suit against the Bastrop Independent School District and three other districts. Representing Minerva Delgado and twenty other Mexican-American parents, the suit charged segregation of Mexican children from other white races without specific state law and in violation of the attorney general's opinion. In addition the suit accused these districts of depriving such children of equal facilities, services, and education instruction. Judge Ben H. Rice of the United States District Court, Western District of Texas, agreed and ordered the cessation of this separation by September 1949. However, the court did allow separate classes on the same campus, in the first grade only, for language-deficient or non-English-speaking students as identified by scientific and standardized tests applied to all.
The Delgado decision undermined the rigid segregation of Mexican Americans and began a ten-year struggle led by the American G.I. Forum and LULAC, which culminated in 1957 with the decision in Herminca Hernandez et al. v. Driscoll Consolidated ISD, which ended pedagogical and de jure segregation in the Texas public school system.