Between those two poles of explanation American views of immigration have oscillated. On the one hand, as Patton reminds us, immigrants were judged to be noble souls, tugged by the lodestone of American opportunity, whose talents and genius and love of liberty account for the magnificent American character. On the other hand, as in Ross's view, especially if they had the misfortune to arrive on a more recent boat, immigrants were thought to be degraded, freeloading louts, a blight on the national character and a drain on the economy—the kind of people described all too literally, so the argument goes, by Emma Lazarus's famous inscription on the base of the Statue of Liberty: "your tired, your poor . . . the wretched refuse of your teeming shore."

Yet for all their differences, the two views have several things in common. Both explain immigration in terms of the moral character of immigrants. Both understand immigration as a matter of individual choice. And both implicitly invoke the American magnet as the irresistible force that put people in motion, drawing them either to opportunity or to dependency.

Those concepts do not bear close analysis as adequate explanations for the movement of some 35 million human beings over the course of a century. This was a historical phenomenon too huge and too specific in time to be sufficiently accounted for by summing 35 million decisions supposedly stimulated by the suddenly irresistible gravitational attraction of a far-off continent.

The Push of Europe

For the first three centuries or so after the European discovery of the New World the principal source of immigrants to the two American continents and the Caribbean was not Europe but Africa. Only in the early nineteenth century did the accumulated total of European settlers in the New World exceed the approximately 10 million Africans who had made the trans-Atlantic voyage in the years since 1492. To explain the African diaspora by citing entrepreneurial instincts, the love of democracy, or the freely chosen decisions of migrants to follow the lodestar of American promise would be a mockery. Clearly, the involuntary movement of those 10 million Africans is best explained not in terms of their individual characters and choices but in terms of the catastrophically disruptive expansion of large-scale plantation agriculture and its accursed corollary, large-scale commercial slavery.

A comparable—though, to be sure, not identical—element of involuntariness characterized emigration from nineteenth-century Europe. Any generalization about what prompted a phenomenon as long-lived and complicated as the great European migration must, of course, be subject to many qualifications. All discussions of the migration process recognize both push and pull factors. But at bottom the evidence convincingly supports the argument that disruption is essential to the movement of people on such a scale. And, as in the African case, the best, most comprehensive explanation for a process that eventually put some 35 million people in motion is to be found in two convulsively disruptive developments that lay far beyond the control of individual Europeans. Those developments had their historical dynamic within the context of European, not American, history.