In Why We’re Polarized, American progressive journalist, political commentator, and podcaster Ezra Klein argues that Americans are divided into two sharply contrasting groups rooted in partisan identities.

He writes that the clustering of nearly the entire electorate into the Democratic and Republican camps is a story about identity. Specifically, our partisan political identities have become overarching super-identities that encompass and activate our most deeply felt personal, religious, linguistic, socioeconomic, and ethnic/racial identities. In today’s America, these underlying lines of division all come together in one main division—between Democrats and Republicans—that makes bipartisan cooperation increasingly difficult.

In this guide, we explore the origins of modern political polarization and its differing impact on the two major political parties, how polarization has made American politics a winner-take-all struggle, and ideas for how we might depolarize our politics. We also supplement Klein’s ideas and analysis with commentary from other political scholars and analysts and explore additional perspectives that both support and challenge Klein.