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.