Great Depression–era migrants heading to California’s “garden of Eden” ran into trouble on the state’s borders with Arizona, Nevada, and Oregon. Woody Guthrie sang about their troubles in the song, “Do Re Mi.” “Now the police at the port of entry say/ ‘You’re number fourteen thousand for today,'” is how Guthrie put it.

The “police” in the song were from Los Angeles. Deputized by local sheriffs starting in February 1936, LA police officers halted incoming trains, automobiles, and pedestrians. They were looking for “vagrants” “indigents” “tramps,” and “hoboes”—all those with “no visible means of support.” As historian H. Mark Wild reveals, Guthrie’s song is a virtual documentary of the Los Angeles Police Department’s blockade against poor white migrants looking for a new life.

California had a history of racist exclusion against Chinese and Japanese immigration. As Wild explains, African Americans were not welcomed. Mexicans and American citizens of Mexican descent were deported by the thousands when the Depression hit. Nonwhites were portrayed as “lazy, criminal, diseased, or predatory” and a threat to the jobs of whites.

But the westward migration from the Plains states during the Depression was overwhelmingly made up of native-born whites. Racial exclusion obviously wouldn’t work in their cases, but similar reasoning would be applied against them.

“Border patrol advocates maintained that the newcomers’ predicament derived not from economic conditions but from cultural deficiencies,” Wild writes. Poor whites “lacked the work ethic and moral character to become part of the the Los Angeles community.”

Los Angeles had developed as a “bastion of conservative, pro-business sentiment” that appealed to middle- and upper-class white Protestants. That appeal was very successful in the 1920s, when 2.5 million people, many of them middle-class midwesterners, moved to a California that welcomed them with open arms.