The concern about the impact that immigration impose on American society is not a new one. Since the discovery of the New World immigrants from all over the world moved to American continent in search of a better life, that this vast and rich in sources, yet scarce in population land had promised them. Soon the immigrants outnumbered the native population. They came from England, Europe and Asia. In addition, millions of Africans were imported as slaves. By 1700 the United States became a country of immigrants and more were still to come. At ....