#15. The US had a “visiting workers” visa program during WW2 which did just what you suggested in terms of allowing foreign workers to enter the US, under a work contract arrangement.
The worked the “garden crops” on the East Coast, the apple picking seasons all over the country, esp. the NW regions, I think some of the sugar cane areas of Louisiana (which existed back then), citrus fruit in Florida, and as miners esp. in the SW.
Most miners came from Mexico while East Coast workers came from Jamaica and some other smaller islands
This was due to the shortage of American men needed for the war effort.
While the working conditions often were not very good (which was a shame on us), the average worker made enough money to return home and have a much better standard of living than many of his neighbors (and could buy a land plot for their own farming, or a truck, set up a small business, etc).
This would help resolve a part of the illegal immigrants issues (a let the workers take their earnings home to build up their country). I assume that they would also pay taxes and possibly Social Security. It would all be determined by the terms of their contract between private companies under the guidance of the US Government and, as in the case of at least Mexico, with their government.
....there are more than a few million people of Indian and Pakistani decent still working under expired “visiting workers” visa program...