The most powerful leader of the new government was the secretary general of the Iraqi Ba'ath Party, Ali Salih al-Sa'di, who controlled the National Guard militia and organized a massacre of hundreds—if not thousands—of suspected communists and other dissidents following the coup.

Factionalism, coupled with the ill-disciplined behaviour of the National Guard, led the military wing to initiate a coup against the party's leadership; al-Sadi was forced into exile in Spain.

Michel Aflaq, who saw himself as the leader of the pan-Arab Ba'athist movement, declared his intent to take control of the Iraqi Ba'ath Party.

The "Iraq first" wing was outraged, President Arif lost patience with the Ba'ath, and the Party was ousted from government on 18 November 1963.

The next day, without mentioning al-Sadi, Radio Baghdad announced that the ruling Ba'athist Party was now led by a 15-member council headed by al-Bakr.