From the early 1970s Saddam was widely recognized as the power behind President al-Bakr, who after 1977 was little more than a figurehead. Saddam reached this position through his leadership of the internal security apparatus, a post that most senior Baʿathist figures had been too squeamish to fill. Saddam, however, had drawn hard lessons from the party’s failure in 1963 and resolved that no dissent should be allowed in party ranks, no opposition outside the party should be tolerated, and ideological commitment to party ideals alone was insufficient to guarantee the loyalty of internal security officers. Kinship bonds were, to him, much more promising. President al-Bakr concurred on that issue, and soon after the Baʿath takeover al-Bakr appointed his young relative (both al-Bakr and Saddam belonged to the tribe of Āl Bū Nāṣir) to the powerful posts of deputy chairman of the RCC, deputy secretary-general of the RL, and vice president. Al-Bakr also allowed Saddam to form the Presidential Guard, mostly from members of the Āl Bū Nāṣir and allied Sunni tribes. Between 1968 and the mid-1970s Saddam became the unchallenged leader of internal security. After he jailed, executed, or assassinated the regime’s opponents, he turned against his own opponents inside the ruling party, using the same tools and methods: a plethora of ubiquitous and ruthless internal security organs loyal to him personally.
https://www.britannica.com/place/Iraq/Iraq-under-Saddam-Hussein