How to prevent military coups.

• Position: In African countries

African countries with powerful militaries and a few strong competing ethnic groups are most likely to suffer military coups and related ethnic strife, a recent study revealed. Researchers also found that nations with an educated and politically aware population and a high level of foreign investment tended to have fewer coup attempts.

These results provide clues as to how the U.S. and the United Nations best can promote stability in places like Somalia, indicates J. Craig Jenkins, professor of sociology, Ohio State University, who conducted the study with Augustine Kposowa of Wayne State University. The key is to deal with the ethnic tensions that rack many unstable countries, while realizing that military force isn't always a solution.

"There is a military class that has come to power in many African states that sees itself through an ethnic lens," Jenkins explains. "They see themselves as members of a tribe or ethnic group, rather than citizens of the country, and they work to protect their group.

"If there are two or three big ethnic groups, it leads to an unstable condition. The situation is more stable if you have one dominant...