Have you ever wondered why so much of the world seems to be almost perpetually embroiled in war? Or why so many conflicts appear to reach a resolution, only to break out again after a short lull?

Traditionally, these disputes are analysed in terms of ethnic, tribal or political conflict. But traditional analysis hasn't served the world very well, if we are to judge matters by the results. Whether it's Colombia or the Democratic Republic of Congo, peace initiatives come and go but the wars go on.

Now it's the turn of the economists to come up with an explanation. Dr Paul Collier, research director of the World Bank, in particular, has argued that guerrilla groups and civil wars are driven by "greed not grievance".

Collier's controversial, even cynical, take on the economic causes of conflict makes for compulsive and persuasive reading.

His study ignores the rhetoric of revolution and concentrates on what people do and, in particular, what they do with their money.

The results are surprising. One of the chief causes of conflict is a country's dependence on commodity exports, he finds. In Angola, for example, the Unita rebel movement earned about $2 billion (#2.3 billion) from diamond mining in the first two years of renewed war, prompting Collier to quip: "diamonds are a guerrilla's best friend". But take away the oil or the diamonds, and countries relapse into peace, as in the case of Mozambique.

One factor that perpetuates conflict is the existence of a large diaspora. Large, wealthy expatriate communities, usually in the US, can make life more difficult for those left behind in post-conflict situations (just think of Northern Ireland in this context).

What is striking about this study is the finding that inequality, a lack of democracy, or ethnic and religious divisions - all the usual sources of grievance - do not make a country more prone to conflict. Countries with one dominant ethnic group, such as Sri Lanka or Rwanda, are more at risk. Collier's conclusion is that "civil wars occur where rebel organisations are financially viable". The Michigan Militia has only a handful of part-time volunteers, while the FARC rebels in Colombia employs about 12,000 people. This is because the FARC earns about $700 million a year from drugs and kidnapping, while the Michigan Militia is broke.

So while public perception holds that rebels are "public spirited heroes fighting against injustice", economic analysis sees rebellion as "more like a form of organised crime". As for well-meaning rebel supporters, they "may simply have been duped", says Collier.

Many rebel movements are just "the rage of the rich", he claims. For example, Katanga was the copper-mining region of Zaire, from which it tried to secede; Biafra was the oil-producing region of Nigeria; and Aceh is the equivalent in Indonesia.

This thinking is beginning to permeate an aid community desperate to find a new paradigm for resuscitating the poorest countries. As Stephen Jackson, director of the International Famine Centre in UCC, noted last year: "War may no longer be about winning, but simply about sustaining and maintaining a climate of uncertainty within which economic exploitation can take place."

In Sierra Leone, for example, Jackson wonders "whether the violence currently tearing the country apart is supported by diamond extraction, or whether diamond extraction is supported by the war".

One solution is for the international community to make it more difficult for rebel groups to sell the commodities that they loot. Collier also suggests that countries be helped diversify away from dependence on commodities, and to improve income levels and basic services.

Redrawing borders, splitting countries and moving populations to create greater ethnic homogeneity are "the road to increased civil conflict", he says. Look at Yugoslavia, which was diversified and peaceful; then Slovenia and Croatia left and civil war broke out.

Collier mightn't have all the answers but he at least provides fresh thinking. Most of all, though, his theories underline the truth of the old maxim, that "money is the root of all evil".

[SBX] Collier's paper can be accessed at www.worldbank.org /research/ conflict/ papers Paul Cullen is development correspondent with The Irish Times