Conventional population studies usually focus on fertility and mortality figures, and demographers have helped to shape national debates with their analyses of both. As their work has become a sophisticated science, it has also been a political hot potato: many people consider that a nation's fertility, or population growth, is a sign of its health, wealth, and greatness, and demographers have been expected to predict the declines or increases in national power. Yet they nave been stow to assess the consequences of international migration, even while huge population movements are breaking the boundaries of national sovereignty and creating volatile and dangerous political disputes.This groundbreaking book insists on the new, unavoidable truth: large international migrations have permanently altered many countries in the world and have transformed their politics. The noted demographer Michael Teitelbaum and the historian Jay Winter together explore the implications of these changes in the United States, Canada, and Europe. They believe, and prove, that it is essential to understand the demographic forces at work in our societies if we are to arrive at a politics of nationhood that treats people decently and generously.