Sadiq al-Mahdi (born 1936, also known as Sadiq Al Siddiq) is a Sudanese political and religious figure.
Sadiq al-Mahdi is head of the National Umma Party and Imam of the Ansar, a sufi sect that pledges allegiance to Muhammad Ahmad who claimed to be Islam's messianic saviour, or the Mahdi.
Sadiq al-Mahdi was Prime Minister of Sudan on two occasions: first briefly in 1966-67, and second starting in 1986, when he formed a coalition government comprising the Umma Party (which he led); the National Islamic Front (led by his brother-in-law, Hassan al-Turabi); the Democratic Unionist Party (led by al-Sayyid Muhammad Othman al-Mirghani); and four small Southern parties. In 1989, his government was overthrown in a coup led by Omar Hasan Ahmad al-Bashir. The post of Prime Minister of Sudan was then abolished.
His tenures in power were mired in instability and controversy including allegations of nepotism, disadherence to due process and the arming of Arab tribes in Darfur, namely the Messiria and the Rizeigat tribes during the late 1970s when he politically led an extra-territorial military incursion into Sudan from Libya through the Darfur region, and in the late 1980s when he was Prime Minister of Sudan. Regarding the allegations of nepotism, many members of Sadiq al-Mahdi's family were given prominent Ministerial roles while he was Prime Minister, including Mubarak al Fadil al-Mahdi, who was Interior Minister in the late 1980s, a period during which many human rights abuses have been documented. Sadiq al-Mahdi famously flouted the Sudanese constitution when he spearheaded the campaign to expel the Communist members of Sudan's parliament in the late 1960s.
He is also the uncle of Alexander Siddig who is best known for playing Dr. Julian Bashir on Star Trek: Deep Space Nine.
He is the author of a variety of scholarly and political books, including The Southern Question (1964); Speeches in Exile (1976); Questions on Mahadism (1979); Legitimate Penalties and Their Position in the Islamic Social System (1987); Democracy in Sudan: Will Return and Triumph (1990); Challenges of the Nineties (1991).
He is a member of the Club of Madrid.