Immigration is a contentious issue in the industrialized nations of the world. This is true not merely in traditional receiving countries, such as the United States, Canada and Australia, but in recent decades also in Europe, which historically experienced net emigration. In Europe, for example, support has risen in recent years for virulently anti-immigrant political parties, such as the National Front in France, the National Alliance in Italy, and the Republikaner in Germany. The debate has a particularly interesting twist in those countries most of whose residents are themselves descendants of immigrants. The inscription on the Statue of Liberty exhorts the world to “give me your tired, your poor, your huddled masses yearning to breathe free….” Yet there has always been a tension between this open-door philosophy and fear of the economic and social impact of the next wave of immigrants.