Demographic research suggests that by 2050, America’s Asian, Hispanic, black, and mixed-race populations will have increased while the white population will have decreased. The percentage of Latinos, for example, will increase from 10.2 percent to 24.5 percent, and the Asian population will increase from 3.3 percent to 8.2 percent. In the meantime, the percentage of whites in the population will decrease from 74 percent to 53 percent, while the black population will remain fairly stable, rising from 12 percent to 13.6 percent.

Some analysts worry that higher birthrates among Asian and Hispanic Americans, along with an increase in immigration from Asia and Latin America, is a threat to national unity. They fear that America could become gripped by dangerous racial and socioeconomic conflicts as competing ethnic groups fight to promote their interests at the expense of all others. If this happens, these analysts maintain, the United States...