As a technoid, with wide experience in the use of tools to build boats, houses and vehicles, I'm concerned about the degradation of infrastructure building and repair when it becomes politically correct to hire illegal aliens.
So much money can be saved by contractors by skipping union labor, which is accountable and usually highly skilled, due to the apprentice system and relatively high pay, that there is a race to the bottom.
My last job before I retired showed me some very frightening tendencies under the illegal alien labor system.
During six years renting construction tools in Oakland, California, in the center of the Fruitvale districts, very heavily Mexican, I had many occasions to observe people doing just that.
Very often, people were hired off the street, taken to our rental place, given the barest instruction in English on tools such as jackhammers, front loaders, concrete mixers, demolition drills, or rebar benders, and then taken to the worksite.
Some of the results were chilling: people driving Bobcat 753's over embankments, mixing very weak cement for columns holding up houses on steep hills, blocking and jacking entire houses on narrow supports, using oily rebar (the cement doesn't stick to it), improperly placing rebar and webbing, all the things you'd expect of people who never went to school, didn't speak the language, and were completely unaccountable for any mistake they make.
Supervision was a joke. Crews of ten or more unskilled workers would be left doing complicated work like wiring houses, installing insulation, plumbing, roof trusses, etc. on their own, and just picked up in the evening.
Skill costs money, and although houses are overspecified, no-one really knows by how much. This is in mudslide and earthquake country.