Familiarity of African-American vs. alienness of Mexican as ethnic outgroup, Southern culture. / BB&W 127.
Neil Foley, "Partly Colored or Other White: Mexican Americans and Their Problem with the Color Line," in Beyond Black and White: Race, Ethnicity, and Gender in the U.S. South and Southwest, ed. Stephanie Cole and Alison M. Parker, 123-144 (College Station: Texas A&M University Press, 204), 126-127.
By the middle of the 1930s it was clear in Texas and other parts of the American West that African Americans did not constitute the number one  race problem, as they had historically in the states of the South, including East Texas. In the West the threat to whiteness came principally from Latin America, particularly Mexico, not from Africa or African Americans. African Americans, after all, were not “alien” or foreign, and whites had a long history of dealing with blacks. In Texas and other southern states, whites and blacks had grown up together in the same towns, even if Jim Crow laws prevented them from sitting at the same lunch counters or attending the same schools. Blacks, for their part, shared much of southern culture with whites, whether on cotton farms or in Baptist churches. Indeed, African Americans in Texas shared wit hwhites the experience of being displaced from their farms by Mexican immigrants whose language, religion, and customs differed from those of both blacks and whites.
Blacks, whatever else they might be to whites, were therefore not “alien,” a word reserved by nativists to describe immigrants. Although many Mexicans had lived in Texas long before Stephen Austin established the first Anglo settlement in 1822, Anglos still regarded Mexicans as alien culturally, linguistically, religiously, and racially.