One unexamined explanation for the terrible violence in Sierra Leone may well be the fact that the country has the world's most unequal distribution of income. This is unlikely to change by force of arms -- indeed, greater access to education is the only possible remedy. PNS editor Andrew Reding is a fellow of the World Policy Institute who specializes in human rights and Latin America.

Why is Sierra Leone, a country blessed with diamond riches, disintegrating into social chaos despite the best efforts of UN peacekeeping forces?

One clue, so far unexamined, is the fact that it has the world's most unequal distribution of income.

Income inequality is measured by the Gini index on a scale of 0 to 100 where zero represents perfect equality -- all inhabitants have the same income -- and 100 represents perfect inequality, where a single person receives all of a country's income. Neither extreme occurs in reality.

The most egalitarian countries have a Gini index in the 20s. European countries like Germany, Austria, Belgium, Hungary, Poland, Norway, and Sweden all fall in that range, according to World Bank figures. Canada and Australia are just over 30. The United States is around 40.

Once inequality rises above 50 percent, disparities become glaringly obvious, to the point where they undermine a society's sense of unity and common purpose. Latin American countries, notorious for contrasts between posh neighborhoods and shantytowns, cluster in the 50s. They are equally notorious for their instability. War-torn Colombia, for instance, is at 57.

But Sierra Leone takes the prize. At 63 percent, it offers the world's most extreme example of inequality. And one of its most extreme examples of instability.

Interestingly, both inequality and instability are often made worse by valuable natural resources. Just as Colombian cocaine and oil buy guns rather than educational opportunities, so do Sierra Leone's abundant diamonds. Since access to education is linked to income, civil war, far from addressing disparities, aggravates them through social disintegration.

It is no coincidence that Sierra Leone's brutal rebels developed their primary social base among the illiterate peasants of the northern, inland parts of the country. Their resort to Marxist terror mirrors that of the Shining Path guerrillas in Peru and of the Khmer Rouge in Cambodia, both of which built social bases among the neglected, illiterate peasants of the hinterlands.

Casual indifference to human life is born of dehumanization, which in turn tends to occur whenever distinctions between human beings become so great that those on at least one side of the divide stop seeing those on the other side as having anything in common with them. That is what is now happening in Sierra Leone, and the carnage is being made worse by the rebels' access to modern armaments purchased with diamonds.

At considerable cost, the United Nations can intervene, as it now must for humanitarian reasons, to restore order. But such interventions will become more frequent unless the causes of social disintegration are addressed.

Economic development is the answer, but only if such development is tied to improved access to educational opportunity throughout the society. A large part of the reason for Sierra Leone's present predicament is that the British colonial authorities developed a good educational system in the capitol, while neglecting the rest of the country. In that context, economic development concentrates wealth in the hands of an educated elite, with disastrous results.

That is why trade agreements and foreign aid should be conditioned on commitments to increase investment in education, and to aggressively expand educational opportunities for the most marginalized sectors of countries that presently suffer from high rates of inequality. Only by reaching out to the outcasts will we be able to forestall the emergence of additional brutal insurgencies that shock our sensibilities but are in large measure born of our neglect.