I am all for closing the borders and controlling the flow of migrants, but it's not just a matter of wages....in wealthy urban/suburban centers you can't find any American willing to say...dig.
I know plenty of people in the landscaping biz, and construction trade. They advertise jobs in the paper and the pay scale for labor intensive jobs start at ten bucks per hour and goes up quickly. I have no idea how many of these people working are actually illegal. If they're working for a large employer, they have fake SS numbers, which are obviously NOT being flagged the the SS admin. Remember, currently an employer can not check the authenticity of a number untile AFTER the individual is hired, which is not something a busy employer will even bother with. The employer is also advised NOT to fire someone with a bad number, but go back to them and advise them that they may have made a mistake. The SS admin is complicit in all of this.
We have plenty of "poor" people and teenagers who are NOT applying for these jobs. Pass any road crew in the DC area and you will only see hispanics working.
Again....it's NOT the wages, it is the type of work. It may not be so in other parts of the country that are not as wealthy, but here, not even low income people want to do labor intensive work.
Actually, this is not true. You cannot ask about citizenship status until an offer is made. Under the Fair Credit Reporting Act, you may verify the validity of a ss number, review criminal background history, and conduct numerous other personal checks provided the candidate signs a release.
It's pricey, but I've hired over 5000 people in my career and validated every single one.