Mauritania became independent from France in 1960. However, it did not join the United Nations until 1961 due to an initial veto by the Soviet Union. The Arab League disapproved of Mauritanian independence due to Morocco's ambitions for Mauritania. Eventually, Mauritania was admitted to the United Nations in 1961 in response by the Soviet Union to a favorable vote for Mongolia's admission in the same year. Mauritania did initially support France in Northwest Africa to counterbalance Morocco's ambition. By 1962, however, Mauritania turned away from wholesale support of France and began normalizing relations with its neighbors, eventually establishing diplomatic relations with Mali in 1963 through the Treaty of Kayes, Algeria and the United Arab Republic in 1964. In 1963, Mauritania joined the Organization of African Unity, which then caused Morocco to resign. At this point, Mauritania, encouraged by the OAU and the Arab League, did not seek diplomatic relations with Apartheid South Africa, Israel or Portugal. Today, however, Mauritania has normalized relations with South Africa and Portugal, with the downfall of the Apartheid system in South Africa as well as the retreat from colonialism in Portugal.
In 1976, when Spain withdrew from the Western Sahara, Mauritania annexed a third of it. Upon this, both Algeria and Morocco withdrew their ambassadors from Mauritania. The rebel Polisario group began raids on Mauritania in 1976 and lasted until 1979 when Mauritania withdrew its claims from the Western Sahara and recognized the Sahrawi Arab Democratic Republic as the sovereign government of the Western Sahara territory, though Morocco took control of the SADR because of Mauritania's withdrawal. Since this time, Mauritania has declared neutrality in the dispute, seeking a peaceful and expedient end to the conflict; diplomatic relations with Algeria and Morocco have resumed.
Following a military coup d'état in 2005, Mauritania's membership in the African Union was suspended "until the restoration of constitutional order in the country". This left Mauritania diplomatically isolated within Africa, as it left Mauritania the only country on the African continent except Morocco without full membership in the African Union. In March 2007 democratic rule was restored in Mauritania, with presidential elections declared "free and fair" by international observers, though after the 2008 coup membership was once again suspended.
