The Popular Movement of the Revolution (Mouvement Populaire de la Révolution, abbr. MPR) was the ruling political party in Zaire (known for part of its existence as the Democratic Republic of the Congo). For most of its existence, it was the only legally permitted party in the country. It was founded by Joseph-Désiré Mobutu (later Mobutu Sese Seko) on 20 May 1967. The official ideology of the MPR, as laid down in the Manifesto of N'sele in May 1967, incorporated "nationalism", "revolution", and "authenticity". Revolution was described as a "truly national revolution, essentially pragmatic," which called for "the repudiation of both capitalism and communism." One of the MPR's slogans was "Neither left nor right," to which would be added "nor even centre" in later years. Nevertheless, historians consider Mobutu's regime to be right-wing and there is evidence of economic liberalization during Mobutu's rule as he appointed Léon Kengo wa Dondo, a prominent advocate of free market reform, as prime minister. Some historians, such as Michel Ugarte and Max Liniger-Goumaz, argue that Mobutu's Zaire was part of a phenomenon called "tropical fascism" due to its authoritarianism, anti-communism, and Third-Positionist rhetoric. From its formation in 1967 to 1990, the MPR was de facto the only legal party in the country. The 1967 constitution explicitly allowed the existence of two parties. However, the MPR was the only party allowed to nominate candidates in presidential and parliamentary elections held in November 1970. A month later, on 23 December, the constitution was amended to formally declare the MPR to be the only legally permitted party. The 1974 constitution enshrined the MPR's status as the vanguard of the nation. It stated that "there exists a single institution, the MPR, incarnated by its President," that the "President of the MPR is ex officio President of the Republic, and holds the plenitude of power exercise," and that "Mobutism" was constitutional doctrine. All citizens of Zaire became members of the MPR at birth.