It's a complex situation, and it's unfortuante that politicians pander to the demand for simplistic answers..

That's not the case in my 35 years of owning houses with roofs.

The guys doing the labor, whether on the roof or helping the electrician may be fairly clueless; the men in charge of the job are not. With them, you only have to worry about sifting out the crooks from the honest contractors.

This, of course, becomes the rationalization behind the desire by some (those hiring the roofers and hiring all kinds of employees, including tech employees on H1-B visas) to support, defend, and even demand admission of more immigrants.

This is where McCain offends people, because many immigrants refuse to assimilate (insultingly compounded by multicultural down-with-the-USA activism and entitlement-engorging “immigrants' rights” left-wing activists and Dem Party future-booster-seekers) and because businesses often exploit immigrants; there are many lazy natives in this country (in large part due to the entitlement mentality that is the legacy of decades of Dem accomplishments), but also because many of the jobs don't pay much (and with more immigrants admitted, will pay less).