@McTag,
It is interesting to note that every wave of immigrants to this country, starting with Germans in the 1840s and going through the successive waves of Irish, Eastern European Jews, Italians, Poles, Swedes, Czechs and Hungarians that followed, was accompanied by more or less the same public outcry about the alien forces distorting our society that accompamnied them. Each was subject to more or less the same initial discrimination, epithets and isolation and each followed more or less the same 2-3 generation ascent in the economy and society. After that period none of it mattered very much any more and some new flavors had been added to the common culture. Indeed the friction was generally greatest between the most recently arriving groups as they competed in their respective ascents up the economic ladder.
This may not be a universal or permanent pattern. We had lots of space for expansion during that period, and that likely enabled a good deal of the solution.
Europe has, by contrast a long pattern of cultural and linguistic competition and even conflict. Some of these historical strains are still occasionally evident. The mass movements of Germans Poles, Czechs and others that followed WWII is an often forgotten legacy of the wars of the 20th century. The EU has gone a very long way to tempering these issues, but the waves of immigrants reaching Europe over the past few decades, and particularly now, bring even greater cultural challenges for assimilation than the inter European movements of the past..