By late 1967 Mobutu had successfully neutralized his political opponents and rivals, either through co-opting them into his regime, arresting them, or rendering them otherwise politically impotent. Throughout the late 1960s, Mobutu continued to shuffle his governments and cycle officials in and out of the office to maintain control. Kasa-Vubu's death in April 1969 ensured that no person with First Republic credentials could challenge his rule. By the early 1970s, Mobutu was attempting to assert Zaire as a leading African nation. He traveled frequently across the continent while the government became more vocal about African issues, particularly those relating to the southern region. Zaire established semi-clientelist relationships with several smaller African states, especially Burundi, Chad, and Togo.