How do societies respond to great demographic change? This question lingers over the contemporary politics of the United States and other countries where persistent immigration has altered populations and may soon produce a majority minority milestone, where the original ethnic or religious majority loses its numerical advantage to one or more foreign-origin minority groups. Until now, most of our knowledge about large-scale responses to demographic change has been based on studies of individual people’s reactions, which tend to be instinctively defensive and intolerant. We know little about why and how these habits are sometimes tempered to promote more successful coexistence.

Justin Gest is an Associate Professor of Policy and Government at George Mason University’s Schar School of Policy and Government. He is the author of six books, primarily on the politics of immigration and demographic change—all from Oxford University Press or Cambridge University Press.