Today, BBC correspondent Jonah Fisher reports
This week President Bush met Minni Minnawi, one of the rebel leaders from Darfur in western Sudan. Mr Minnawi is the only rebel leader there who has signed up to a peace deal, but there are fears that this has made matters worse in the region.
Photo: President Bush urged Mr Minnawi to build support for peace
As the sun beats down on Darfur's dry flat desert, the order goes out from a leader to his men: "Solve lora infernis, unleash hell! We will not tolerate this any more."
These men are not the Janjaweed - the feared militia backed by the Khartoum government and responsible for the worst atrocities of this war. A hundred thousand people have died and two million have been displaced.
They are not the Darfur rebels either - a sprawling mess of armed groups who have targeted aid workers and food convoys.
No, this is the African Union (AU) - the organisation sent to bring peace to Sudan's far west.
Barking out the orders is a man who would not be out of place in a Hollywood film - South African sector commander Richard Lourens.
A veteran of wars in Angola and Namibia, he is not a man who takes failure well.
Sporting a closely trimmed black beard and a macho swagger, he has been in Darfur just a few months but he has had enough of being pushed around in this messy conflict.
Large parts of the surrounding desert are off limits to his patrols and twice in the past two weeks Colonel Lourens' men have suffered the ultimate military humiliation.
Stopped by rebels on a road, the South African soldiers handed over their weapons and vehicles without a shot being fired. Some 45 machine guns and four vehicles were taken.
As Colonel Lourens reads the riot act, the man at the centre of Darfur's confusion is being acclaimed in Washington as a peacemaker.
For Minni Minnawi, a photo opportunity with President Bush is his reward for bowing to international pressure and signing an African Union-sponsored peace agreement with the Sudanese government.
The problem is that Mr Minnawi's signature has made the situation in Darfur worse, not better.
SLA forces are dividing along tribal lines
A former primary school teacher, Mr Minnawi leads his own faction of the Sudan Liberation Army (SLA) - the only rebel group in Darfur to have agreed terms with the Khartoum government.
But the deal has done little for the region's traumatised population and new rebel alliances spring up every few days.
The one positive note is that fighting has now stopped between Mr Minnawi's rebel faction and the Sudanese government.
But with both hands now free he has been able to devote his full attention to what had previously only been a side issue - attacking rival rebel leaders and their supporters.
In one of the African Union camps I spoke to a West African commander. He loaded a detailed map on to his laptop.
"This town is Korma," he said.
Korma and the surrounding villages are dominated by a tribe loyal to SLM Wahid, a rebel group which is opposed to Mr Minnawi and outside the peace agreement.
Taking me through events in meticulous detail, the commander explained how Mr Minnawi's rebels spent the first few days of July clearing villages of people en route to capturing Korma.
At least 80 people had been killed, he said, 18,000 fled for their lives.
"This was ethnic cleansing," he told me. Remaining villagers were being shot on sight, and he said he had seen pictures of two mass graves.
'Part of the problem'
Mr Minnawi's violence has left the African Union humiliated and deeply compromised. When the deal was signed the AU had welcomed him with open arms.
The rebel leader stays inside AU headquarters, eats AU food and his men drive, and on some occasions crash, AU cars. Atrocities have been brushed under the carpet and when Mr Minnawi wants to go into the field, an African Union helicopter is made available to fly him there.
The men of the African Union went to Darfur to help protect its displaced people.
Now they are seen as part of the problem: on the side of the Sudanese government and of Minni Minnawi. They are not welcome in many of the camps they are supposed to be protecting and despite the best efforts of people like Colonel Lourens, their men are demoralised.
Western donors have seen enough.
They want the AU's troubled mission to be replaced by a United Nations force.
President Bush apparently made his support for this proposal clear to Mr Minnawi when the two men met at the White House on Tuesday. But the Sudanese government firmly opposes it. A holy war will greet any western invading force, Sudan's President Omar al-Bashir has declared.
So now it seems the AU will stay here in Darfur at least until the end of the year.
A donor conference was held so they could ask for funds to beef up their operations and try to implement fully the peace deal.
The response was lukewarm. They were given only half the money they needed - just enough to continue stumbling along their current path.
Having pushed a partial peace deal onto Darfur the world seems to be walking away from a mess it helped to create.
Out in the desert again, Colonel Laurens is speaking to his men.
"Enough is enough," he shouts.
"We came here to be friends with our African brothers, but that's over. If they raise their weapons at you again - kill them."