Not all ethnic groups are politically active or engage in ethnic conflict. Depending on the political structure of the state (democracy versus authoritarian regimes) and the size and situation of the ethnic minority (large versus small portion of the society, regionally concentrated versus dispersed), ethnic groups will have different claims and will use different means to voice their demands. The Minorities at Risk Project at the University of Maryland began tracking ethnic groups in 1986, and it developed six types for categorizing the groups: ethnonationalists, indigenous peoples, ethnoclasses, communal contenders, religious sects, and national minorities.

• Ethnonationalists are large, regionally concentrated ethnic groups with a history of autonomy or separatist struggles.

• Indigenous peoples are original inhabitants, or descendants of the original inhabitants, of a colonized territory. These groups typically have traditional social, economic, and cultural customs that set them apart from the rest of the society. Even though indigenous peoples are often notably different from the dominant group (they usually are set apart not only by physical markers but also by language, religion, traditions, etc.), they tend to be badly organized, have weak connections among group members, and, consequently, are usually unable to voice their claims (mostly to land and access to resources) in a successful manner. As a result, indigenous peoples are among the most-marginalized ethnic groups in the world.

• Ethnoclasses are physically or culturally distinct groups who are typically descendants of slaves or immigrants. In many cases, these groups perform distinctive economic activities, mostly at the bottom of the economic hierarchy. Ethnoclasses generally strive for equal treatment, economic opportunities, and political participation. Mobilization of these groups varies widely. Ethnoclasses have successfully pursued their interests in many Western democracies, but they remain relatively unorganized in most other places.

• Communal contenders are culturally distinct groups that have or desire a role in state power. Some of them can also be classified as ethnonationalists opting for separatism and seeking independence. The Minorities at Risk Project distinguishes between dominant, advantaged, and disadvantaged communal contenders. Dominant groups hold both political and economic power over other groups in their societies. Advantaged groups enjoy political benefits but are not in control of governing power. Disadvantaged communal contenders are the most common, and they often face political or economic discrimination or both. Changes to group relations involving communal contenders are particularly likely if power structures change. Intergroup shifts of relative political influence and economic prosperity can provoke violent reactions, which tend to be particularly long-lasting and disastrous. Power-sharing models that take differences and external changes into account are the only way to deal with these issues. However, as history shows, such power-sharing arrangements are often very difficult to achieve.

• Religious sects are ethnic groups that differ from the rest of their society mostly by their religious beliefs and related cultural practices. Religious minorities tend to have high group cohesion because religion is a highly salient trait. In addition, religious groups usually already possess an organizational structure, which makes mobilization of the groups particularly easy and likely. For these politicized religious minorities, their faith is what sets them apart, but their goals are political in nature (e.g., participation in the government, nondiscrimination, or the recognition of the minority).

• National minorities are groups with kinfolk in a neighbouring state but who are a minority in the state in which they reside. Most of these groups have a history of political autonomy, which they strive to reinstate.

Causes of ethnic conflict

In several scholarly articles, Michael Edward Brown provided a useful approach to understanding the causes of ethnic conflict. In those articles, he distinguished between underlying causes and proximate causes. Underlying causes include structural factors, political factors, economic and social factors, and cultural and perceptual factors. Proximate causes embrace four levels of conflict triggers: internal mass-level factors (what Brown calls “bad domestic problems”), external mass-level factors (“bad neighborhoods”), external elite-level factors (“bad neighbors”), and internal elite-level factors (“bad leaders”). According to Brown, both underlying and proximate causes have to be present for ethnic conflict to evolve. This section first summarizes what Brown described as the “four main clusters of factors that make some places more predisposed to violence than others”—the underlying causes—and then presents the four catalysts, or triggers, that Brown identified as proximate causes.