I will have to be selective in my response to a good discussion, with quite different viewpoints.
How immigrants voted in nineteenth century mattered much less because the government did so little. Governments spent a very small proportion of income, so taxes were very low-no income tax in particular- and few government benefits were given to anyone. The situation in all these respects is radically different now. That is why I do not believe unlimited immigration is any longer the right solution for the US.
One of you would like to extend the benefits received by the American poor to poor peoples in other countries. Unfortunately for such sentiments, someone has to pay for these benefits, and American taxpayers, rich, middle class, and poor, all agree in not wanting to do this. Shouldn't they be the ones to decide how their money is spent?
I have argued in earlier entries in this blog that I favor much expanded legal immigration. I was amiss in not repeating this position in my discussion of illegal immigration. However, I neglected to discuss this mainly because I do not feel it would solve the illegal immigration issue, particularly if preference is given to more skilled migrants. To be sure, the acceptance of a sufficiently large number of legal immigrants of all types would largely eliminate illegal entrants, but this is another solution that is certainly not politically feasible, and questionable on some of the grounds discussed in my posting.
I based my claim about the price of coyotes on a study by Christina Gathmann when she was a student in the economics department at Chicago. She had an admittedly limited sample of data on coyote prices and other matters concerning illegal crossings. The price did not seem high even for poor immigrants, since they could have repaid the cost with less than a weeks earnings in the US.
Basic economics does imply that the price of coyotes would rise if greater barriers to crossing raised their costs. This would include the greater likelihood of being punished when apprehended.
We already have a law that stipulates that employers of undocumented workers can be punished. This has not been enforced, partly because of the prevalence of forged documents. Perhaps we now have the technology of making forgeries more difficult. If so, then employer punishment is certainly one way to cut down on illegal entrants.