The constitutional basis for "bilingual education" programs in America ultimately derives from Lau v. Nichols, which was unanimously decided by the U.S. Supreme Court in 1974. This decision held that the placing of non-English-speaking children in regular public school classrooms violated the equal protection provisions of the 1964 Civil Rights Act, and that special assistance must be provided to such students to compensate them for their language difficulties. However, the Court did not specify the precise form which such special assistance should take, and in particular did not require that "bilingual education" or native-language instruction be provided.
In 1978, the Ninth Circuit Court of Appeals (whose jurisdiction includes California) decided Guadalupe v. Tempe, clarifying the issue of language assistance raised by Lau v. Nichols. In this decision, the Appelate Court explicitly and emphatically held that "bilingual education" was not required under the U.S. Constitution or the 1964 Civil Rights Act and that providing extra English language assistance to students was a perfectly adequate means of satisfying the requirements of Lau v. Nichols.