How do you know the Sudanese diplomat is lying? His lips are moving. The world would do well to remember this old chestnut, because on August 29 the United Nations Security Council is supposed to determine whether the Sudanese government has sufficiently disarmed the Janjaweed militias that it has directed and trained for more than a year and a half. The Security Council apparently hopes that the Sudanese government will arrest enough of these marauders to make the Darfur region of Western Sudan safe enough for the efficient delivery of food and medicine by international organizations.

A noble goal, but the chances of this happening are slim. For one, American diplomatic sources tell me that the members of the Security Council are not much up for invoking punitive measures against Khartoum, given the implicit threat from China, which owns a controlling stake in Sudan’s national oil company, to veto anything that smells of sanctions. For Beijing and many European capitals, there is still much diplomacy to be done on the Darfur issue. After all, Kofi Annan’s new envoy to Sudan, Jan Pronk, is still negotiating with the government and will not likely finish his assessment of the situation in Darfur in time for the U.N. to actually get around to punishing a regime that both houses of Congress have said is aiding and abetting a genocide.

Mr. Pronk could save us all a lot of time. He need look no further than the London Daily Telegraph for strong evidence that Sudan is once again not living up to its side of the bargain. On Monday the paper published an interview with Janjaweed leader Musa Hilal, one of seven members of this foul militia the State Department has already accused of war crimes. In the interview, Hilal bragged that the Sudanese government that asked him to organize a campaign of rape and murder against swathes of villages would never be so stupid as to actually incarcerate him.

Or Mr. Pronk could examine Sudan’s staggering record of unfulfilled commitments. When the National Islamic Front government came to power through a coup in 1989, it quickly violated agreements its predecessor made with the U.N. to insure the safe delivery of food and medicine to regions in the south under rebel control. Until 2002, Khartoum routinely bombed villagers as they made their way to food dropped by small planes and denied access to doctors seeking to inoculate its citizens against preventable diseases. This policy earned the NIF the ignoble distinction of presiding over one of the last places on earth where people still ran the risk of contracting wild polio.

In 1997, the NIF signed what at the time was heralded as a peace agreement with southern rebel leader Riek Machar, allowing this non-Muslim into a government widely praised by Muslim fundamentalists like Osama bin Laden for its intolerance of infidels. He soon left the regime after Sudan’s military launched a policy to incinerate villages along the proposed path of a new oil pipeline. When the pipeline became operational in 1999, it provided the army with enough capital to purchase Eastern European attack helicopters it put to devastating effect in its war with the south.

In April of this year, Sudan signed what was called a cease-fire with Darfuri rebels. Then the government claimed that it had no connection to the Janjaweed militias as those marauders fouled wells with the dead bodies of freshly slaughtered adolescent boys.

Diplomats who insist on negotiating with these thugs will point with pride to a cease-fire agreement in the Nuba Mountains. After years of fighting, Sudanese negotiators allowed in late 2001 for international aid organizations to feed the non-Muslim residents of this disputed territory. Indeed this is a triumph for diplomacy – except that according to the terms of the deal Sudan agreed not to redeploy its troops to other parts of the country where they could continue killing. Yet the troops were redeployed. The problem required yet another negotiation in February to create verification and monitoring teams to ensure that the troops in Nuba would not be sent to other regions of the country. To this day, Sudanese compliance with these terms is spotty.

But the real accomplishment for diplomacy with Sudan is the north-south cease-fire. Since June when the general outlines of this agreement were forged, there has been much less fighting. But this is only half the story. Under the terms of the American-negotiated agreement Sudan must share power with its longtime foes from the south. Given the fact that the Sudanese still require Christian schools to use Muslim textbooks, is it reasonable to expect the regime will turn over power to animists and Christians?

On August 29 the Sudanese ambassador in New York will likely make an impassioned plea that the fate of the displaced Darfuris has improved since the U.N. demanded his government arrest their tormentors. Maybe this time his colleagues will not listen. No doubt his lips will be moving.