The roots of the Darfur crisis, a humanitarian emergency in western Sudan that threatens the lives of roughly a million displaced people, aren’t as simple as the slogans suggest. What is clear is that, as Annan said on his plane, the dysfunctional Khartoum government knows it has “lost the propaganda war.” And for good reason: although the violence is diminishing, and an expanded aid pipeline has begun to flow smoothly, innocent African farmers have been raped, executed and starved by nomads known as Janjaweed (“armed horsemen”) who served as proxies for the Sudan government.

Although widely understood as purely an ethnic conflict, this tragedy stems from politics mixed with tribalism. Darfur is home to 85 tribes, roughly divided between farmers and herders forced to compete as the Sahara advanced. The most influential are the Zagawa, Muslim Africans whose homeland straddles the Sudan-Chad border. In 1998, the ruling Islamist clique in Khartoum split. The winner of this power struggle, President Omar al Bashir, jailed or purged important Zagawa Army commanders and government ministers, core supporters of Islamist dissident Hassan al-Turabi. They then made common cause with John Garang, a former enemy who heads the southern-based Sudan People’s Liberation Army, which had been at war with the Khartoum government since 1983. The dissidents joined the top ranks of the Darfur-based Sudan Liberation Army and the smaller Justice and Equality movement, both of which seek regional autonomy. The breakaway group also cultivated ties with Chad President Idriss Deby, himself a Zagawa, and Eritrean President Isaias Afawerki, who supports a separatist group on Sudan’s eastern border.

Under intense U.S. pressure, Khartoum and the southern rebels two years ago agreed to a ceasefire and entered peace talks. Soon the Darfur rebels, not bound by the ceasefire, began to attack government police garrisons and airports in the region, using new weapons and vehicles. (Musa Hilal, 43, whom Washington calls the “coordinator” of the Janjaweed, says he simply let his followers serve in uniform in the Army and government militia after the attacks provoked a general mobilization. “Some innocent people were really affected by the war,” he told NEWSWEEK. “Politicians are exploiting this.”) Opposition sources in Khartoum say a prominent adviser to the SPLA raised $1 million for the Darfur offensive, and that both Eritrea and the southern rebels secretly backed the uprising. The SPLA and Eritrea deny supplying the Darfur dissidents with weapons or money. Asked whether SPLA leader Garang inspired the rebellion as a negotiating ploy, Annan said, cryptically, “That idea is there.” The U.S. State Department’s top Africanist, Charles Snyder, says he sees no evidence of such provocation.

Garang, who under the terms of a framework peace agreement signed in May will join the central government, clearly wants allies in Darfur. If the accord is smoothly implemented–by no means a certainty–he can run for president in three years. Garang could win if he can add enough Arabs to his core African constituency, which includes about a third of the country’s voters. “Darfur is a [political] contingency plan,” says an opposition source in the capital. “In a nutshell, it is a struggle for power in Khartoum.”

Nobody seems to have anticipated how badly Darfur’s civilians would suffer. The United States has asked Khartoum to disarm the Janjaweed, and last week introduced a draft U.N. resolution that would impose sanctions on its leaders–and perhaps on government leaders in Khartoum–if violence in the region did not stop within “days,” according to Secretary of State Colin Powell. But it’s not certain that Washington would win a vote on the resolutions in the U.N. Security Council. A French diplomat calls the conflict a civil war, and suggests sanctions might plunge the country back into more widespread conflict.

No U.N. action is likely before July 15, when a U.N.-Sudanese committee will assess Khartoum’s efforts to tamp down violence. Sudan’s foreign minister last week warned Washington not to create a “new Iraq” by imposing sanctions. This time the Bush administration is likely to stop at threats.