Wealthy democracies don’t become dictatorships. For a generation that adage has provided one of the firmest laws of modern democratization, the equivalent for comparativists of the democratic peace among international relations scholars. Like any big claim, the link between economic wealth and democratic durability has provoked debate. Political scientists have parsed the data, questioned the mechanisms involved and pursued new projects that validate the proposition even as they refine it. They have explored whether wealth not only sustains democracy but also produces it, and whether the distribution and forms of assets matter more than their raw amount.