is concerned, there has long existed a conflict in the United States between (at its emotional extremes) the starry-eyed idealists and the hard-hearted xenophobes, be- tween the Pollyannas and the Chicken Littles. Does the current wave of new arrivals represent a serious threat? Is the situation out of control?
Some Americans clearly think so. "In the 19th century," former Ambassador Clare Booth Luce observed last year, "the United States absorbed 40 million immigrants. But the...