Sudan has been riddled by civil conflict since it’s independence in 1956. This has to a great extent stemmed from the political dominance of Muslim, Arab northerners over the non-Muslim Southern population. Two civil wars have decimated the country. The second, from 1983 to 2005, was estimated to have displaced 4 million people and caused 2 million deaths. However, the 2005 Comprehensive Peace Agreement brought relative peace. These meetings established the Government of national Unity and a Southerner (currently Salva Kiir) became the Vice-Presidency of the country.
The Peace Agreement which gave the Southern militarised opposition - the Sudan Peoples’ Liberation Army - autonomy to rule the South for 6 years was followed by a referendum which resulted in the south's independence in July 2011.
Sudan remains a vast country – bordered by Egypt, Libya, Chad, Ethiopia and Eritrea - countries whose own internal problems have been known to spill into, or combine with the regional instabilities of their neighbour. This is particularly the case with Chad/Darfur and the former border with Uganda/South Sudan in which refugees, proxy militarised groups and national armies have crossed over borders with virtual impunity in pursuance of their own particular regional interests or personal security.
The Sudanese national identity is, in the words of Gerard Prunier ‘hopelessly split between and Arab North, Black Christian South and an often overlooked African Muslim West’ (largely referring to Darfur.) John Garang – former leader of the Southern Peoples Liberation Movement – saw revising the rule of Sudan’s majority peripheral populations (not simply Southerners) by a small Arab elite as the fundamental raison d'etre of his movement’s struggle.
Over the last decade, a break-away conflict has also been developing in the Western Darfur region. Since 2003, the Arab-run Central Sudanese Government has been attacking black non-Muslim Africans in Darfur. This started when the Sudan liberation Army/Movement and the Justice and Equality Movement (JEM) - took up arms against the central Arab government, accusing it of oppressing indigenous Black Africans in the region. The Janjaweed, a militia group comprised of Afro-Arab tribesman from the North has been carrying out atrocities against black communities in Darfur since the outbreak of violence, purportedly on behalf of the central government.
Darfur is now a humanitarian crisis, with varying estimates placing the number of casualties anywhere between twenty thousand and several hundred thousand. A fragile ceasefire was signed in February 2010, to encourage peace talks but the JEM has recently said it will boycott further talks after allegations of further atrocities by the Central Sudanese government in Darfur. President Bashir was indicted by the ICC due to alleged involvement in the 'genocide' occurring in Darfur.
The peaceful but still contested split from the south has not laid to rest the demons of that conflict, most of the region's oil wealth lies in the south, and there is fierce disagreement between both nations on how to divide the gains from it; the oil rich province of Abyei which borders both countries is scheduled to have a referendum on its national status - a referendum that may result in, or provoke further conflict.
There are various contested explanations for conflict in Sudan and and this brief overview could never fully explain a region with a vast and complex history not easily summarised in a few sentences. For the best information on Darfur specifically, and Sudan in general then visit the African Arguments blog Making sense of Sudan.