Vast growth in the number of states since World War II has coincided with a greater proportion of conflicts being intrastate in nature. This can partly be attributed to internal power struggles resulting from de-colonisation, domestic manifestations of international polarisation during the Cold War, and later structural change coinciding with the end of the Cold War. Yet three domestic factors commonly provide the preconditions for civil or intrastate wars. Firstly, these conflicts depend on ethnic or identity divisions within a state used to justify hostility and mistrust between groups. Secondly, a real or perceived existential threat that motivates one or more groups within a state to rise against another. Thirdly, the political opportunity offered by a weak state. In addition, a number of factors ensure intrastate wars have a transnational dimension. Identity groups cross state borders, there’s the complicity of nearby hostile governments, active ethnic diaspora, and an international regime that facilitates intervention on humanitarian grounds or in the interest of regional stability. All of these structural elements are evident in the conflict in South Sudan since 15 December, 2013.

In the late colonial era Sudan was a jointly British and Egyptian administered ‘condominium’. Borders between Northern and Southern Sudan cut across tribal lands and sometimes shifted to suit colonial administration. Post-colonial Sudan saw two protracted civil wars in the forty years before the Comprehensive Peace Agreement (CPA) of 2005. A succession of oppressive regimes in Khartoum faced uprisings in the west and south of the country – struggles for self-determination by ethnically diverse populations. The politically dominant Arabic northeast of the country, aspiring alternatively to a Socialist, and after the Cold War an Islamist state, reaped the benefits of development, while secularist black-African communities elsewhere in the country, including Sufis, and in Southern Sudan, Christians, were politically and economically repressed. Under the leadership of John Garang, the Sudan People’s Liberation Army and Movement (SPLA and SPLM) fought a civil war against successive regimes in Khartoum from 1983 to 2005 that was not essentially secessionist, but which sought political and economic empowerment for the tribes of Southern Sudan.

This period of conflict produced many of the ethnic atrocities that today contribute to divisive identity myths fanning the civil war in newly independent South Sudan.

Garang didn’t live to see South Sudan’s independence on 9 July 2011 amid optimism and unity across its diverse population. Both Garang and his successor, Salva Kiir, came from Dinka tribes who represent the largest ethnic group in South Sudan. Reconciliation in 2002 between Garang’s SPLM and Nuer leader, Riek Machar, contributed to the achievability of the CPA. Machar had split from the SPLA/M in 1991 and through the 90s undermined the movement with the initially covert support of Omar al-Bashir’s regime in Khartoum. Khartoum has long fuelled division within rebel movements, and is accused of complicity in the conflict in post-independence South Sudan. Machar is implicated in the 1991 Bor massacre, an event which contributes to mistrust between Dinka and Nuer, South Sudan’s second biggest ethnic group. Vice-President since independence, Machar fell out with President Kiir in July 2013. In the ensuing conflict Machar is accused of fanning Nuer mistrust of numerically superior Dinka to exploit division, as he did during the 1990s. War since 2013 has resulted in 500,000 additional refugees and 1.5 million internally displaced people.

At independence in 2011 some matters remained unresolved from the CPA – the demobilisation of former SPLA in South Kordofan and Blue Nile states on the Sudan side of the border, and the self-determination and territorial boundary of the border region of Abyei. Prior to July 2013 most observers saw these as the biggest threats to peace in South Sudan. Al-Bashir’s regime is accused of repression and ethnic cleansing in these three border regions. In Abyei, a permanent Dinka population once coexisted with Mesiria, a nomadic Arabic tribe who occupy the northern part of the region periodically each year. Through most of the colonial era Abyei was administratively within the border of Southern Sudan. Before Sudanese independence in 1956 the border was redrawn, placing Abyei within northern Sudan. In the months leading up to South Sudan’s independence in 2011, ethnic violence culminated in Khartoum’s military occupation of Abyei. The crisis was diffused by the insertion of Ethiopian peacekeepers under a UN and African Union mandate.

In security terms, a weak state is one that doesn’t hold a monopoly on coercive violence. At the time of independence, South Sudan’s security was underwritten by political and economic support from the US and by AU troops, not only Ethiopian peacekeepers in Abyei but also by Ugandan soldiers operating in Western Equatoria along the borders with Central African Republic and Democratic Republic of Congo, where Joseph Kony’s incursions faced no South Sudanese defence. It’s in this context that from his ethnic Nuer base in Unity, Upper Nile and Jonglei states, Riek Machar has been able to mount a violent campaign against Kiir’s government, and indeed in the capital Juba.

The behaviour of colonial powers continues to influence postcolonial intrastate conflict for decades. Regional and global geopolitics affect the relative power of a state and its opponents. However, the recent conflict in South Sudan demonstrates that exploitation of ethnic division and historic grievance, the insecurity of an identity group, and the opportunity posed by a state’s weakness are more important factors leading to intrastate war.