The United States, between the 1880’s and 1924, admitted about 4 million Italian immigrants. As Leon Wieseltier, a senior fellow at the Brookings Institution, observed to me, “We got Enrico Fermi, Frank Sinatra, Joe DiMaggio, Antonin Scalia — and Al Capone. Who in their right mind would suggest that the Italian immigration was not a great blessing for our country?”The argument that immigrants are criminals is rather silly, just another version of our ancient habit of displacing all blame onto outsiders. The more interesting arguments about immigration have to do with culture. Many people want their worlds to stay pretty much as they are, and mass immigration changes things. Vast swaths of London have about them little that is little English, just as many Parisian suburbs are not very French. Many small towns in Oklahoma and Nebraska are now more than half Hispanic, with more Spanish than English spoken in the streets and more taqueritas than diners. Personally I don't care, but many people do. After all, the basic point of nationalism is that each culture or "nation" should have its own independent state to insure the survival of that culture. Many Europeans still think this way, that the main point of Denmark or Switzerland is to preserve the Danish or Swiss way of life.
Call it the Capone Principle: Costs of immigration are outweighed by benefits.
Nationalism has always been something of a fraud, since every substantial block of territory is ethnically and culturally diverse; whatever cultural unity modern nation states have has been imposed by the state. But in our American "nation of immigrants" it is even more of a fraud. Is there anybody among Donald Trump's supporters today who thinks admitting all those Italians was a terrible mistake? How about the Germans who so offended Benjamin Franklin? The Irish who were so hated in the 1850s? We have always been a melting pot or salad bowl; and yet some people have always hated that. That just seems to be our way.