Sudanese Socialist Union in the context of Democratic Republic of the Sudan

Gaafar Muhammad an-Nimeiry (otherwise spelled in English as Gaafar Nimeiry, Jaafar Nimeiry, or Ja'far Muhammad Numayri; Arabic: جعفر محمد النميري; 1 January 1930 – 30 May 2009) was a Sudanese military officer and politician who served as the fourth head of state of Sudan from 1969 to 1985, first as Chairman of the National Revolutionary Command Council and then as President.

A military officer, he came to power after a military coup in 1969. Establishing a one-party state, with his Sudanese Socialist Union as the sole legal political entity in the country, Nimeiry pursued socialist and Pan-Arabist policies and close collaboration with Gamal Abdel Nasser of Egypt and Muammar Gaddafi of Libya. In 1971 Nimeiry survived a pro-Soviet coup attempt, after which he forged an alliance with Mao Zedong of China, and, eventually, with the United States as well.

On 25 May 1969, several young officers calling themselves the Free Officers Movement (after the Egyptian officers who instigated the Egyptian revolution of 1952) seized power in Sudan in a coup d'état and started the Nimeiry era, also called the May Regime, in the history of Sudan. Gaafar Nimeiry ruled as president with the Sudanese Socialist Union (SSU). At the conspiracy's core were nine officers led by Colonel Gaafar Nimeiry, who had been implicated in plots against the Abboud regime. Nimeiry's coup preempted plots by other groups, most of which involved army factions supported by the Sudanese Communist Party (SCP), Arab nationalists, or conservative religious groups. He justified the coup on the grounds that civilian politicians had paralyzed the decision-making process, had failed to deal with the country's economic and regional problems, and had left Sudan without a permanent constitution.