The annexation of Western Sahara occurred in two stages: 1976 and 1979. Shortly after Spain gave up control over Spanish Sahara in 1975, both Mauritania and Morocco occupied the territory. On 14 April 1976, the two countries annexed it between themselves via the Western Sahara partition agreement. However, on 14 August 1979, Mauritania renounced all territorial claims to Western Sahara and withdrew its troops, prompting Morocco to extend its annexation to formerly Mauritanian-controlled areas.[1][2][3]
Since World War II, it has been held in international law that any act of annexation is illegal. Likewise, the United Nations regards the Moroccan annexation of Western Sahara as null and void, such that the territory is not a legal part of Morocco and it remains subject to the international guidelines for a military occupation.[4]
As Morocco and the United States have had a close relationship since the former's independence, Morocco has enjoyed full American support throughout the Western Sahara conflict.[5] In exchange for the Israel–Morocco normalization agreement in 2020, the United States officially recognized Western Sahara as part of Morocco, and urged the Sahrawi Arab Democratic Republic to "negotiate a mutually acceptable solution" using Morocco's Western Sahara Autonomy Proposal as the only framework. In 2023, Israel formally recognized Moroccan sovereignty over Western Sahara.[6]
To sum up the legal status: Western Sahara is not a part of Morocco and Morocco has no legal title or claim to the territory. Since the annexation is illegal, it is null and void, and Morocco is therefore, legally speaking, an occupying power. Morocco has an obligation to respect the right of the people of Western Sahara according to the law of occupation and to end its illegal annexation and occupation of Western Sahara.