The situation is different now than during previous waves of immigration. Can you propose a workable policy that would prevent the third worlders who are steeped in Marxism from importing that impoverishing ideology here? Can you envision any way to forma coalition that would support such policies. Both libs and conservatives are pretty unified on opposing open boarders.
You didn't happen to read George Guilder's "Weath and Poverty" did you? I came away from reading that with most of my opinions changed about immigration.