My immigration stance?
My ancestors were accepted into this country as refugees fleeing vicious pogroms in Russia. Why would I ever abandon that most American of ideals, that this is a country that anyone can come to to build a new life?
How does that all that translate into actual legislative language and rules?
The concern with unrestricted movement is that the equilibrium would be when standards of living and subsidies and transfer payments are about the same over the bulk of the population of the world, suggesting over time a rather large decline in the US standard of living, or at least its standard of living vis a vis the world's median.