There was already a thead on that here (or was it in the BBQ PIT?), just a while ago. A couple dudes posted cites showing that ILLEGAL immigration, if ended, would have no significant effect on our economy- no large jump in food prices, etc. Note that legal immigrants take up most of the slack of migrant farm workers, domestic help and such. (Thus, if all legal immigrants & guest workers were kicked out- there would be a significant effect on the economy).
Even when a Illegal migrant takes a job- they are often treated the same as their legal co-workers. There are several reasons for that, not the least of is that: if you are shown with Illegals on your workforce, and you can show that you honestly didn’t know and treated them as legal workers- then there are no criminal charges against the Employer.
Certainly you do read newspaper stories about illegal immigrants semi-forced into working as protitutes or as farmworkers being kept in near serfdom. The reason you read these stories in the papers is that such practices are illegal and* uncommon.*
I have quite a bit of experience working with the Migrant Farm workers here in CA (enough to know that “tu Madre” isn’t Mexican for "Yes Boss’ anyway.
) and from my experience, there are only a few "illegals’ in that workforce (maybe 20%??) and they are treated by nearly every employer the same as legal migrant farmworkers (which isn’t all that great, sure.) There is no “stream of cheap, non-union workers who can be easily exploited” - well, the legal migrants often fall into that caegory, sure. But damn few employers know, or want to know that some of their worked are illegal. It’s kind of “don’t ask don’t tell, and give us some fake paperwork so we can say we checked”.
Finally- the OP is wrong- the USA does NOT “allow illegal immigrants to work”. The Border Patrol tries to stop them, INS rounds them up from time to time, and Employers that knowingly or negligently hire Illegals are fined or jailed.
Sure, the US could do more. A few 10’s of Billions on a “Berlin Wall”, another couple of Billion$ on more Agents, and it’d slow to a trickle. But it would make relations with Mexico very bad, and it doesn’t seem to be worth it. Not only would we all have to pay higher taxes for this, but yes, indeed- maybe a few pennies more for produce. It seems like the American Public doesn’t want that.