The United States’ long-standing broad “catch-all” political parties have historically combined voters from distinct regions of the country, each including both rural and urban dwellers. Since the late 1990s, however, rural Americans nationwide have increasingly supported the Republican Party, while urbanites have persisted in their allegiance to the Democratic Party. The growing rural-urban divide has become mapped onto American polarization in ways that are fostering tribalism. This place-based cleavage is now contributing to the transformation of the nation’s politics and that of many states. It also threatens to have deleterious effects on democracy.