I can tell you some positive impacts:
- Most western countries are concerned about economic cliffs around retirement benefits due to falling population. The US is not because so many people, used to(?), want to move here.
- Our food is subsidized by those willing to work awful hours at awful wages. As a humanitarian I hate this but I suspect most people would be upset to have to eat food picked at wages white Americans are willing to work.
- Most studies show more people equals more production equals more economic prosperity.
The solution to an illegal immigration problem is to loosen immigration rules and create pathways to citizenship.