The march was considered an attempt to bypass the International Court of Justice's Advisory opinion on Western Sahara that had been issued three weeks earlier.

This meant that regardless of which political solution was found to the question of sovereignty (integration with Spain, Morocco, Mauritania, partition, or independence), it had to be explicitly approved by the people of the territory.

[citation needed] However, the reference to previous Moroccan-Sahrawi ties of allegiance was presented by Hassan II as a vindication of his position, with no public mention of the court's further ruling on self-determination.

[citation needed] In order to prepare head off any possible counter-invasion from Algeria, the Moroccan Army entered the far northeast corner of the region on 31 October, where it was met with stiff resistance from the Polisario, by then a two-year-old independence movement.

[6] The sultan Hassan I, for example, had carried out two expeditions in 1886 in order to put an end to foreign incursions in this territory and to officially invest several caids and cadis.

[7] The exercise of this sovereignty had also appeared, according to the Moroccan government, at other levels, such as the appointment of local officials (governors and military officers), and the definition of the missions which were assigned to them.

Despite the overwhelming military and logistic superiority of the Spanish armed forces based in Western Sahara in relation to the Moroccan armed forces, the Spanish government feared that the conflict with Morocco could lead to an open colonial war in Africa, which could put Francoist Spain into question and lead to an abrupt political change or a social instability and disaster.

Therefore, following the Green March, and with a view to avoid war and preserving as much as possible of its interest in the territory, Spain agreed to enter direct bilateral negotiations with Morocco, bringing in also Mauritania, who had made similar demands.

Morocco claimed the northern part, i.e. Saguia el-Hamra and approximately half of Río de Oro, while Mauritania proceeded to occupy the southern third of the country under the name Tiris al-Gharbiyya.

Mauritania later abandoned all claims to its portion in August 1979 and ceded this area to the Popular Army of Sahrawi Liberation (Polisario), but it was instead promptly occupied by Morocco.

Spain is divided between its desire to preserve a good relation with Morocco, its southern neighbor with whom it shares terrestrial borders in Ceuta and Melilla, and its responsibility to the international legality as the former colonial power.

The traditional position of all the Spanish democratic governments until the election of Prime Minister Zapatero had been that the wishes of the Western Saharan population have to be respected, and of support to the organization of the referendum requested by the United Nations.