Oil trumps diamonds. That is the irreducible lesson of the misspent life of Jonas Savimbi, the guerrilla leader who was hunted down and riddled with bullets by Angolan troops last week. Commodities weigh more on history's scale in Angola today than does communism or capitalism. Savimbi turned out to be neither nation-builder nor neocolonial despot: He was, in the end, Africa's Willy Loman, with the wrong line of goods on hand.

The final episodes of Savimbi's long guerrilla war were financed by diamond traders rather than by the ideologues of Communist China (who supported him back when China really was communist) or by the Central Intelligence Agency, which was ordered to back Savimbi by Gerald Ford and later by Ronald Reagan. But Savimbi and his band of tribal warriors could not compete against the much larger resources the Luanda government gathered through its control of Angola's lucrative petroleum deposits.

Africa, Central Asia and other regions of the Third World exist today in a time of commodity wars. These hostilities are fought not for big ideological or political causes, as in the past, but over control of diamond fields, petroleum concessions, coca leaves and poppies that yield narcotics. The trajectory from wars of liberation to wars of profiteering is seen clearly in Angola's Forty Years' War and in Savimbi's abruptly ended career as one of Africa's most skilled guerrilla commanders and charismatic political leaders.

Savimbi's death in a hail of gunfire may not end the struggle, however. The Angolans and their foreign backers may well fight on to the last diamond. War remains the only business open at the entry level to large numbers of dispossessed or merely greedy people in the Third World -- including areas to which the Bush administration is dispatching U.S. forces and military aid to fight terrorism.

The war on terrorism forces Washington to reengage with the Third World on issues of war and peace, largely neglected over the past decade. In this changed political landscape, Americans must keep their eyes open as they choose friends to shore up and foes to tear down. Washington must resist shelling out resources to unsavory characters and regimes that may be intent on dragging the United States into their own conflicts for their own profit.

Wars for control over minerals have been waged with brutality in Sierra Leone, Liberia, the Democratic Republic of the Congo and elsewhere in Africa in recent years. Drug money is at the core of Colombia's civil war and played a role in the use of Afghanistan and Pakistan as platforms for terrorist networks. Market-driven warfare is part and parcel of globalization, and it seems to be at least as brutal and unrelenting as ideological warfare ever was.

Angola's abundant resources, strategic location in southern Africa and ethnic fault lines have made it a pivotal battleground in the different phases of warfare that have engulfed the country since 1961, when a peasants' rebellion quickly expanded into a war of liberation against Portuguese colonial rule. That war ended in 1974 when the demoralized Portuguese army washed its hands of Africa. The Soviet-backed MPLA grabbed the capital and control of the oil fields and brought in Cubans to fight rival Angolan groups, which sought and got help from South Africa and the CIA. The Cold War proxy battle went to the Soviets' clients in Luanda.

Savimbi started his UNITA movement with help from Beijing after Moscow had turned down his requests for aid. But he had no trouble switching gears. And he served the purposes of U.S. ideologues intent on thwarting Moscow and Havana by fighting the MPLA. The manipulation was mutual on all sides.

The collapse of the Soviet Union and of white tyranny in South Africa stripped away external support and much of the mythology used to justify costly interventions that in the end seemed to change little.

Savimbi continued fighting and smuggling diamonds out of the areas UNITA held. But an international embargo on "conflict" diamonds helped strangle his forces, which then resorted to blatant acts of terrorism against Angolan civilians. When he was gunned down, at age 67, Savimbi had become a caricature of overreaching ambition.

The overwhelming sense of waste that Savimbi's death brings is not confined to him or to Angola. By imposing their ideological conflict onto Africa's own post-independence struggles, the two superpowers made a bad situation worse. Washington and Moscow wasted resources, lives, time and their own moral authority in distant struggles they never bothered to understand from the inside. In this respect, at least, the war on terrorism must not resemble the Cold War.