If the USA were to ban all "Non Christian" immigration to their nation (include baring Catholics) in the late 1830s early 1840s on too about 1900 how will this effect immigration to the rest of the new world and European Empires.
Also is it realistic at all too see a large Irish population move to the Catholic nations like Mexico?
I know this would have MASSIVE adverse effects on US industry, but what other issues would we see coming?
(PS. I have several ideas on what might happen, but its not my area of expertise. Any help or comments would be great thanks)