The question in my title implies a premise: that historically the United States has well afforded to be a nation of immigrants—indeed, has benefited handsomely from its good fortune as an immigrant destination. That proposition was once so deeply embedded in our national mythology as to be axiomatic. More than a century ago, for example, in the proclamation that made Thanksgiving Day a national holiday, Abraham Lincoln gave thanks to God for having "largely augmented our free population by emancipation and by immigration."
Lincoln spoke those words when there were but 34 million Americans and half a continent remained to be settled. Today, however, the United States is a nation of some 264 million souls on a continent developed beyond Lincoln's imagination. It is also a nation experiencing immigration on a scale never before seen. In the past three decades, since the passage of the Immigration and Nationality Act Amendments of 1965, the first major revision in American immigration statutes since the historic closure of immigration in the 1920s, some 20 million immigrants have entered the United States. To put those numbers in perspective: prior to 1965 the period of heaviest immigration to the United States was the quarter century preceding the First World War, when some 17 million people entered the country—roughly half the total number of Europeans who migrated to the United States in the century after 1820 (along with several hundred thousand Asians). The last pre-war census, in 1910, counted about 13.5 million foreign-born people in the American population, in contrast to about 22.5 million in 1994. Historians know a great deal about those earlier immigrants—why they came, how they ended up, what their impact was on the America of their day. Whether America's historical experience with immigration provides a useful guide to thinking about the present case is the principal question I want to address. I want not only to explore the substantive issue of immigration but also to test the proposition that the discipline of history has some value as a way of knowing and thinking about the world.