Horowitz, Donald L. “The challenge of ethnic conflict: democracy in divided societies.” Journal of democracy 4, no. 4 (1993): 18-38.
Democratization is a worldwide movement, but it is neither universal nor uniformly successful where it has begun. Some authoritarian or semidemocratic states may be untouched by the democratic movement; others may find ways to thwart the movement at the outset; still others may move along a democratic path, only to have the changes aborted. There are many reasons, of course, why democratization and democracies may fail, among them the resistance of entrenched civilian or military elites, the absence of conducive social or cultural conditions, and inaptly designed institutions. In many countries of Africa, Asia, Eastern Europe, and the former Soviet Union, a major reason for the failure of democratization is ethnic conflict.
Democracy is about inclusion and exclusion, about access to power, about the privileges that go with inclusion and the penalties that accompany exclusion. In severely divided societies, ethnic identity provides clear lines to determine who will be included and who will be excluded. Since the lines appear unalterable, being in and being out may quickly come to look permanent. In ethnic politics, inclusion may affect the distribution of important material and nonmaterial goods, including the prestige of the various ethnic groups and the identity of the state as belonging more to one group than another. Again and again in divided societies, there is a tendency to conflate inclusion in the government with inclusion in the community and exclusion from government with exclusion from the community.