The last two centuries have seen the rise of the nation-state as the dominant political institution around the world. During this period, the colonial empires of varying duration and reach created first by the Portuguese, Spanish, and Dutch, then the French and British, then the Germans and Italians, and finally the Russians and Americans crumbled and were replaced by independent nation-states. However, “state” and “nation” are not always equivalent. In a surprising number of countries, as we discuss later in this paper, autonomist and secessionist movements of varying strength and character remain active. The broad question we consider in this paper is whether decentralization is likely to hurt or help national unity in these “countries at risk.”