John Garang, the founder of the SPLA/M, was the first president of the autonomous government until his death on 30 July 2005. Salva Kiir Mayardit, his deputy, was sworn in as First Vice President of Sudan and President of the Government of Southern Sudan on 11 August 2005. Riek Machar replaced him as Vice-President of the Government. Legislative power is vested in the government and the bicameral National Legislature. The constitution also provides for an independent judiciary, the highest organ being the Supreme Court.