Uganda still won't admit how many troops it sent into South Sudan in December. But those battle-hardened troops, with their helicopter gunships and heavy artillery, were a decisive factor in helping South Sudan's government to avoid a humiliating defeat on the battlefield.
With crucial assistance from the Ugandan troops and weaponry, the government was able to regain control of several rebel-held towns – although at a cost of hundreds of lives in those devastated places.
It was another triumph for Ugandan president Yoweri Museveni, one of the longest-ruling autocrats in Africa, who has dominated Uganda for 28 years. With his tough army and shrewd ambitions, he is emerging as a regional kingpin in East Africa.
But now he is refusing to leave South Sudan, even though this could sabotage the peace talks between the government and rebels. His conduct is raising new questions about the Western strategy of relying on regional military powers to do the dirty work in Africa's most fragile states.
Most Western countries (with the exception of France) are unwilling to send their own troops into African hotspots, so they depend on countries like Uganda. It's a dangerous practice, since the big regional players in Africa have their own vested interests, including economic interests, which can undermine the peace and sovereignty of weaker African countries.
This week, the United States twice insisted that Uganda must withdraw its estimated 1,600 troops from South Sudan. "Now that a cessation of hostilities has been signed, we, along with others, call on Uganda as well as other governments to pull back so that we can move the peace process forward," said Linda Thomas-Greenfield, the U.S. Assistant Secretary of State, in a briefing for African-based journalists on Tuesday.
She noted that the Ugandan troops were originally authorized for very limited duties: securing the main airport in the capital, Juba, and the road between Juba and Uganda. She didn't spell it out, but it is clear that the Ugandan soldiers have gone far beyond those limited tasks.
In an earlier statement this week, a U.S. State Department spokeswoman warned of "serious consequences" and a possible "regionalization" of the conflict in South Sudan if foreign troops do not leave the country. It was a clear reference to the Ugandan troops.
But the Ugandans immediately rejected Washington's demands. They said the United States had no right to give "orders" to others. "We went to help the South Sudanese people when everybody else ran away," a Ugandan army spokesman told the Daily Monitor, a local newspaper.
Mr. Museveni may have uttered a cynical chuckle when he heard the official U.S. statements this week. After all, Washington has been happy to let Uganda do the fighting against U.S. enemies in the arduous battlegrounds of Somalia, the Central African Republic and the Democratic Republic of Congo. It was the Ugandans who have led the fighting against Islamist extremists in Mogadishu and against the brutal warlord Joseph Kony in the jungles of the CAR and the DRC.
Having relied on the Ugandans for those tasks because of the Pentagon's reluctance to get embroiled in African war zones, the U.S. officials might have a hard time convincing Mr. Museveni of the sincerity of their sudden demands that his troops must now withdraw from South Sudan.
The United States – supported by Canada and other Western governments – has a long tradition of letting its local allies and surrogates do the heavy fighting in Africa. This might be the right option in the search for Joseph Kony or the battle against extremists in Mali, where the Western goals are clearly defined, narrowly focused and widely supported. It is more dangerous in places like South Sudan and Somalia, where the situation is much murkier and the intervening forces are neighbouring powers with their own vested interests.
Washington has allowed France to play a key role in fighting extremists in Mali and trying to restore stability in the CAR. It has allowed South Africa and other African nations to do the heavy lifting in the current conflicts in Congo and elsewhere.
More worryingly, the United States has tacitly accepted the decisions by Kenya and Ethiopia to send their forces across the border into Somalia – which they did without bothering to obtain United Nations approval in advance. It didn't complain when Chad sent its forces into the CAR, despite Chad's clear interests in the CAR. It even stood by as Uganda and Rwanda sent troops into Congo in the 1990s (although it did eventually complain when Rwanda continued to interfere in Congo by financing and arming the M23 rebel movement in the past two years).
By accepting those interventions, the United States hoped to stabilize Somalia, Congo and the CAR. But the intervening forces are often bitterly resented by the local population, and they can become a source of instability and occupation.
The U.S. strategy may have come back to bite it in South Sudan. The Ugandan presence in South Sudan is far from neutral, and it conflicts with the goal of reaching a permanent peace. Rebel leaders are furious at the Ugandan military presence in South Sudan. As long as those troops remain, the peace negotiations will be jeopardized.
Lesley Anne Warner, an Africa analyst at CNA's Center for Strategic Studies, has warned that Uganda's role as a combatant in South Sudan is "diametrically opposed" to its supposed role as a peacemaker and a protector of civilians – and this is damaging the process of international mediation in the South Sudan conflict.
Uganda has clear economic interests in its neighbour. It exports hundreds of millions of dollars worth of goods to South Sudan every year, and there are thousands of Ugandan traders making money in the country.
Mr. Museveni has also been an ally of South Sudan president Salva Kiir for many years, and he is a long-standing foe of Riek Machar, the former vice-president who became the rebel leader. The Ugandan president is a military man, a retired general who has used his military as the key source of his power at home and abroad. And he has a long habit of sending his troops into neighbouring countries.
For all of those economic and military reasons, Mr. Museveni will probably do his best to keep his troops in South Sudan as long as possible. And that could make it very difficult for the war-torn country to reach an enduring peace.