The UN Security Council sent a peacekeeping force, Unmiss, to southern Sudan to monitor compliance with the peace agreement. The CPA was followed by some political softening, and al-Bashir’s party NCP co-ruled with Garang’s SPLM. In July 2005, Garang became Vice President under al-Bashir and President of Autonomous South Sudan, but only a few weeks later he died in a helicopter crash. He was succeeded in all posts by SPLM’s Vice President Salva Kiir Mayardit, who, unlike Garang, openly advocated independence for the South.

Soon the co-operation between north and south Sudan began to crack according to agooddir. No federal military force had been trained and the commission that would distribute the oil revenues did not work. In May 2008, fighting broke out in Abyei between the two sides’ armies. More than 50,000 civilians fled.

Following US pressure, the parties agreed to let the Permanent Court of Arbitration in The Hague determine the demarcation at Abyei. After a year, the court ruled that northern Sudan was entitled to two oil fields, but when the government in Khartoum refused to share the revenue from them, southern Sudan withdrew its claim to the entire area.

Elections and referendum

In April 2010, general elections were held throughout Sudan. They consolidated the contradictions between the parts of the country, but in any case they could proceed with preparations for the referendum in the south. New outbreaks led to suspicions that the north side was trying to sabotage the referendum. Particularly serious was the situation in Abyei, where the north side was suspected of trying to drive out residents who were supposed to want to vote for joining the south. In October, negotiations on Abyei stalled and it became clear that the local referendum could not be carried out according to plan. Later, it was also formally postponed indefinitely.

After all, the referendum in the south could take place in January 2011. Not unexpectedly, almost 99 percent said yes to forming an independent state with a capital in Juba.

Despite the joy of the birth of the new state in July, a number of problems persisted. During the first months of the year, a series of bloody battles broke out in several provinces in the south between the SPLA’s government army and rival militias. The SPLM government in Juba accused Khartoum of attempting a coup in the south before Independence Day and suspended cooperation with the government in the north for the time being. In May, regular units from northern Abyei took over and drove away SPLA. Thousands of civilians fled and the capital was reported to have been looted and partially burnt down. The UN, the EU and several Western powers demanded the immediate withdrawal of the North Side and expressed great concern about a new civil war.

The international pressure, and the fact that both sides realized that a new war would be fatal for themselves, led to the battle ax being buried, at least temporarily. Negotiations on Abyei, other demarcation, distribution of future oil revenues and more are postponed to the future. As one of the first countries, Sudan recognized its new neighbor South Sudan when the new state was declared in Juba on July 9, 2011.

Immediately new conflicts

The celebration of the new state had hardly abated before the unresolved issues led to new conflicts. South Sudan accused Sudan of stealing oil delivered from the south for shipment from Sudan and in February 2012 suspended all oil production pending a settlement. Despite the fact that the countries entered into a non-aggression pact, there were sporadic battles over the oil fields in the border area. In April 2012, South Sudanese troops occupied Sudan’s largest remaining oil field, Heglig, following allegations of Sudanese bombing of civilian areas in South Sudan. The Sudanese government suspended all ongoing peace talks.

The fighting spread to other disputed areas along the border, where local militias with ties to the SPLA took up arms against the Sudanese army. After a sharply worded UN resolution  in May 2012, the fighting was stopped and the South Sudanese forces were withdrawn from Heglig. The UN gave the countries a deadline of three months to solve all mutual problems.

Negotiations culminated in a settlement in September that would regulate security issues, trade and oil production. A demilitarized buffer zone would also be set up between the countries, but the demarcation itself would be postponed once again in the future. In 2013, the Government of Sudan froze a series of agreements with South Sudan on security issues and economic cooperation, and when civil war broke out in South Sudan in December 2013, further negotiations stalled.

A bright spot came in June 2016 when new negotiations began after a peace agreement was concluded in South Sudan the year before and a coalition government took office. However, new outbreaks of violence in South Sudan from the summer of 2016 brought the negotiations to a standstill again. A new peace agreement in South Sudan in 2018 raised some hope for resumed negotiations between neighboring countries, but border issues have not yet been resolved.