The Sudan People's Liberation Movement (SPLM) is a political party in Southern Sudan which originated as a rebel movement, with a military wing known as the Sudan People's Liberation Army (SPLA).
In 1983 Sudan's northern dominated, Islamist government abandoned the 1972 Addis Ababa Agreement which had been agreed by President Jaafar Muhammad an-Numeiry's and Joseph Lagu, the leader of the Anya Nya rebel group from the Christian and animist south of Sudan.
The Sudanese government dispatched Colonel John Garang to deal with a new uprising by ex-Anya Nya rebels. Rather than put the rebellion down, Garang joined it, forming the Sudan People's Liberation Army out of the remnants of the Anya Nya and those Sudanese soldiers who were supported the south.
In 1991 dissension amongst the supporters of the SPLM led to the creation of several splinter movements. This severely hampered negotiations with the official Sudanese government.
There were reports that the US was clandestinely supporting the SPLA during the mid 1990s, as well as claims by the Sudanese government that the SPLA was getting aid from Uganda and Eritrea.
In 2005 the Sudanese National Islamic Front government and the SPLM (who joined with main opposition political party in southern Sudan, the National Democratic Alliance of Sudan) signed a peace agreement. The Comprehensive Peace Agreement (CPA) of 9 January, formally recognized the autonomy of southern Sudan and offered the prospect of a referendum on independence. In addition members of the SPLM were given governmental positions and John Garang was made vice president (as well as being president of the autonomous southern nation). John Garang, however, died in a suspicious helicopter crash on 30 July 2005 returning from Uganda. Leadership of the SPLM passed to Salva Kiir Mayardit, who became president of Southern Sudan, and vice president of Sudan.
In 2007 the SPLM withdrew from the Sudanese government citing increased violations of the CPA.