An occasional glance at a newspaper is all it takes to learn that diversity of the kind that is supposed to benefit the United States is a problem wherever it is found. Every large-scale and intractable blood-letting, be it in the Middle East, Ireland, Burundi, or the former Yugoslavia is due to “diversity,” that is to say, people who differ from each other trying to live in the same territory.

Most of the time, the reasons for discord are not even as salient as race. They can be religion, language, or ethnicity. From time to time, Americans have fought each other for these reasons, but race is the deepest, most constant source of antipathy. Unlike language or religion, race cannot change. Differences between men that are written deep into their bodies will always be a source of friction.