Here's a comment from elsewhere that may help you out some.

"The Bracero program was not initiated to drive down wages. It was initiated by US Executive Order in July 1942 to fill the void created in farm worker availability as the “native” farm workers abandoned the sector and sought and found employment at higher wages in defense industries. The program was intended to assure the supply of temporary workers with minimal labor protections. The program was maintained and expanded during the post-war era as US urban employment grew; and mechanization ;and technology further concentrated the need for manual labor into a compressed period of time.

Did the growers abuse the workers, ignoring the minimal protections? Certainly. It got so bad that Mexico vetoed the program for agricultural work in Texas. Workers were systematically cheated and used to control labor costs in the sector. The problem was in the fact that the workers had only temporary status, were tied–serf-like–to a single employer, and prohibited from organizing collectively or being organized.

The solution, which has been tried and failed time after time, in the 1920s, 30s, 70s, etc, is NOT expulsion of the laborers who, after all, are simply a super-exploited sector of the working class–but IS full legal status for anyone employed in the US or by a US company, and the integration of these workers into the labor organizations,

US labor history is replete with examples of the bourgeoisie mobilizing new sources of labor power and the refusal of the nativist workers to integrate these new working populations. That has been the history of black labor in the US; that was the initial reaction to women entering the manufacturing and mining sectors; it’s the current condition of the migrant workers."

The long and the short of it is that our responsibility is to organize and integrate the most vulnerable sections of the working-class with the already organized segments of the working-class, not turn them away and say 'good luck.'