If we didn’t have MFN and welfare for illegals, the only folks coming here would be those wanting to BE Americans.
Also, without our government continually hamstringing our industries with idiotic regulations and Union authored protectionism... We’d still be the manufacturing center of the World.
Also, factor in private property Rights. If the ranchers/property owners along the border used their Second Amendment to protect their lands from invaders... Do you really think that wouldn’t have an affect on illegal border crossing?
Libertarianism may be a “simplistic ideal” in some peoples viewpoints... But then again, so is the Constitution and it works just fine if you actually FOLLOW it.