Immigration is the most volatile foreign policy issue in the world today. Since the end of World War II, developed countries have allowed over 100 million foreign nationals to resettle within their borders. Governments had to carefully manage the tensions between economic incentives and special interest groups that favored increased immigration, on the one hand, and restrictionist public opinion, on the other. This book points out that the concrete policies countries pursued often differed considerably, depending on which political body—the executive branch, the legislature, or a local authority—made the key decisions. Bodies more vulnerable to public opinion adopted restrictive policies, whereas those less so chose more open policies. As an analysis of how developed countries have gotten where they are today, this argument seems persuasive. But it might miss the contemporary forest for the historical trees. Today, as the author concedes in the conclusion, advocates of immigration find themselves beleaguered everywhere. Public opposition to immigration has grown so virulent that even highly insulated political institutions cannot protect politicians from the backlash against it. As a result, nearly every developed country has adopted more restrictive policies toward immigrants (including those seeking to unify their families), asylum seekers, and refugees.