I remember the bracero program. It worked well for the farmers and the Mexicans. The ones who hated it were the Mexican-American farm laborers (those whom Caesar Chavez was organizing) who felt it depressed wages for them and other American unions (remember in the '60s the unions were pretty strong) who wanted to have higher wage union crop jobs.
Lehrer was (is?, I think he's still kicking around Santa Cruz where he taught math for many years) quite a liberal, but he was not politically correct. I loved his line in the song about "Old Mexico":
How I'm longing to get back
to the land of the Wetback
And forget the Alamo!
In Old Mexicooooo. Ole!
Nobody was "Politically Correct" (except Marxists) in those days. The term had not yet been invented (except for Marxists), and we still had Free Speech in the US and Britain. 1984 was just a novel (tho' a good one).