to Polisario. In 1978 the army seized control of the Mauritanian government and Polisario declared a cease-fire, on the assumption that Mauritania would withdraw unconditionally. This eventually occurred in 1979, as Mauritania's new rulers agreed to surrender all claims and to recognize the SADR. Following Mauritania's withdrawal, however, Morocco extended its control to the rest of the territory, and the war continued. Through the 1980s, the war stalemated through the construction of a desert sand berm, the Moroccan Wall. Sporadic fighting continued, and Morocco faced heavy burdens due to the economic costs of its massive troop deployments along the Wall. To some extent aid sent by Saudi Arabia, France and by the USA relieved the situation in Morocco, but matters gradually became unsustainable for all parties involved. Cease-fire In 1991, Morocco and the Polisario Front agreed on a UN-backed cease-fire in the Settlement Plan. This plan, its further detail fleshed out in the 1997 Houston Agreement, hinged upon Morocco's agreement to a referendum on independence or unification with Morocco voted on by the Sahrawi population. The plan intended this referendum to constitute their exercise of self-determination, thereby completing the territory's yet unfinished process of decolonization. The UN dispatched a peace-keeping mission, the MINURSO, to oversee the cease-fire and make arrangements for the vote. Initially scheduled for 1992, the referendum has not taken place, due to the conflict over who has the right to vote. Two subsequent attempts to resolve the problem by means of a negotiated political settlement by James Baker, acting as Personal Envoy of the UN Secretary General, the first in 2000 and the second in 2003, failed to gain acceptance, the first being rejected by the Polisario and second by Morocco. Both attempts, the first referred to as "The Framework Agreement" and the second commonly referred to as "The Peace Plan", contained the proposal of autonomy for the region under Moroccan sovereignty as core elements of the plans. Failure to gain acceptance by the parties to either proposal was a result of what each of the parties viewed as fundamental flaws in the respective proposals. The Framework Agreement would have required the parties to agree on the specific terms of a political settlement based on the Autonomy/Sovereignty formula through direct negotiations. Baker presented the Peace Plan as a non-negotiable package that would have obliged each of the parties to accept its terms without further amendment. Both proposals