no lasting resolution has been achieved to date. The ceasefire was upheld until 13 November 2020 when the Moroccan army entered into the demilitarized town of Guerguerat, and the Saharawi authorities responded by declaring that the ceasefire was broken and the SPLA armed forces attacked Moroccan army positions along the Moroccan Western Sahara Wall. Referendum and Houston agreement The referendum, originally scheduled for 1992, was intended to give the local population of Western Sahara the option between independence or affirming integration with Morocco, but it quickly stalled. In 1997, the Houston Agreement attempted to revive the proposal for a referendum, but likewise has not met with had success. , negotiations over the terms of any potential referendum have not resulted in any substantive action. At the heart of the dispute lies the question of who qualifies as a potential voter; the Polisario has insisted on only allowing those found on the 1974 Spanish Census lists (see below) to vote, while Morocco has insisted that the census was flawed by evasion and sought the inclusion of members of Sahrawi tribes which escape from Spanish invasion to the north of Morocco by the 19th century. Consequently, both sides blame each other for the stalling of the referendum, and little progress is likely to be made in the near future. Efforts by the UN special envoys to find common ground between both parties did not succeed. By 1999 the UN had identified about 85,000 voters, with nearly half of them in the Moroccan-controlled parts of Western Sahara or Southern Morocco, and the others scattered between the Tindouf refugee camps, Mauritania and other locations throughout the world. The Polisario Front accepted this voter list, as it had done with the previous list presented by the UN (both of them originally based on the Spanish census of 1974), but Morocco refused. As rejected voter candidates began a mass-appeals procedure, the Moroccan government insisted that each application be scrutinized individually. Continuing disputes between the two factions once more brought the process to a halt. According to a NATO delegation MINURSO election observers stated in 1999 that "if the number of voters does not rise significantly the odds were slightly on the SADR side". By 2001, the process had reached a stalemate, and the UN Secretary-General asked the parties for the first time to explore other solutions. Indeed, shortly after the Houston Agreement (1997), Morocco officially declared