I live in California where immigrant labour does almost all the dirty jobs.  every construction site, every low-rent auto repair shop, every corporate ag field of pesticide-laden gmo pseudo-food, every hotel cleaning staff, every restaurant kitchen, has its complement -- up to 100 percent -- of Spanish-speaking low-wage labour.  every big hardware store, every morning, has the same crowd of Hispanic men and boys waiting outside, hoping to be picked up as casual day labour by the (mostly Anglo of course) contractors as they drive by in their huge trucks and SUVs.  pass by around noon, and you see the dispirited rejects -- elderly, youthful, scrawny, whatever -- still trying to look strong and able as they court an ever-diminishing chance of making any money that day.  a fair percentage of this "flexible" (as our pundits of race-to-the-bottom econ love to say) labour force is "illegal," paid under the radar, paid in cash and well below the going rate for legal, documented Anglos.  and it is a labour force that can't complain -- the threat of being turned over to la migra is always there, the employer's ace up the sleeve.

so this issue is in my face, day after day.  Anglos in California take for granted that the weary guy trying to sell strawberries on a street corner, the gardener's heavy labour crew, the grunt labour for the roofing contractor, the guys who tent and spray for termite poisoning when houses are sold -- all the jobs that mean back breaking effort, sweating for hours in the hot sun, and exposure to heavy toxicity -- are "Mexicans."  that's just how it is.  and at the same time, the Anglos who feel these jobs are not good enough for them, complain about "Mexicans coming here and taking our jobs."

when I was young I worked in an auto shop -- a dubious auto shop run by a Mexican immigrant who had wealth or connections or both to start with, and had parlayed these into business ownership.  he brought countrymen in through a network of friends and family.  working alongside these guys as a junior grease monkey I got to hear some of their stories.  one gently-spoken, grave and courteous guy told me he was qualified as a lawyer back in Mexico City, but the economy was very bad and there were no jobs, so he was making more as a mechanic in el Norte than he could back home.  the shop owner used to amuse himself by chucking small lit firecrackers onto the shop floor when the guys were working under cars and trucks.  he found it funny if he could get a worker to start violently enough to hit his head on the underbody.

anyway, it was an eye opener for me at the age of twenty, a work experience I never forgot -- the feudal authority of the shop owner, the bitter dignity of some of the workers, how you could tell who had legal papers and who didn't.  California is in this sense an apartheid state:  there are two classes of labour and the division is mostly racial.  there are workers who have unions and ombusdmen and due process and OSHA rules, and then there is a Dickensian subculture of intimidated, underpaid, undervalued Gastarbeiter.

political harm is of course done in several ways.  racial tension is exacerbated between the low-cost immigrant labour and demographics who used to do those same jobs -- poor whites, poor Blacks.  a downward pressure is exerted on wages generally when "we can always get some Mexicans who will work for less" -- especially useful for union-busting.  and the immmigrant labour force serves as an ideal scapegoat for the job-destroying policies of the corporate elite, the offshoring and downsizing and whatnot.  the real reason you (or your young-adult children) don't have jobs, mister, is those darned immigrants.  never look upward, only downward or sideways.

I think all of the above helps to explain the insanity at the border and the appalling indifference of US public opinion.  Americans feel afraid, and rightly so -- standard of living eroding, employment uncertain, health care often nonexistent or brutally unaffordable -- and the idea of Defending Our Borders against an external, infiltrating force that can be blamed for our troubles is seductive.  doesn't hurt at all if that force speaks a different language and is darker complexioned than the Aryan ideal.

The difference between theory and practise in practise ...