Empires historically possessed a unique ability to organize diversity and successfully rule over people quite different from one another. The national states that succeeded them in Europe were organized on the basis of nationality (real or imagined) where diversity in language, ethnicity, or religion was...

Humanity’s future existence hinges on cooperation on a global scale. The greatest existential threats we face are worldwide problems that stem from the man-made climate disaster—and the massive decline in biodiversity, pollution, worsening storms, fires and sea level rise that come with it. Even the...