Expanding legal immigration reduces illegal immigration, again
It's quite obvious, when given an option to follow an easy set of rules most people choose to do so
If you make it easier to do something legally which is currently mostly illegal, the illegal share of the total will decline. This argument is often used to argue for legalising prostitution, hard drug use, gambling etc. I don’t say there’s nothing to this argument. The USA’s experience with alcohol prohibition was not great, after all. But the problem is, however lax you make the laws, there’s still an edge. You legalise marijuana and cocaine, but that still leaves fentanyl.
With immigration, as long as you exclude any category of person at all from having an automatic right to enter your country at whim, people in that excluded category will have an incentive to try and enter illegally. Exclude those with criminal convictions from legal immigration, and those people will try to immigrate illegally.
At this point, it’s probably worth pointing out that there are countries which make legal immigration relatively hard, but which don’t thereby suffer from super-high levels of illegal immigration: Japan and South Korea, for instance.
What's the difference between them coming in illegally and changing the rules to allow them in legally? Don't you end up with the same number of illiterate 3rd world peons and their lineages in perpetuity either way?
How about parole for Mexicans.