The hostile nations surrounding Israel have sent thousands of men across its borders in a violation of the internationally recognized boundaries of the Jewish state. While Israeli prime minister Benjamin Netanyahu has called this influx an invasion, a variety of United Nations officials defended the infiltrators as innocent “demonstrators.” International law has a clear answer to the question who is right.

For this is not the first time in modern Middle Eastern affairs that an Arab autocracy has used massive marches of nominally civilian personnel to invade and undermine a neighboring state. In the past, such attempts have been denounced by the international community for what they are: a use of force against the territory of another state in violation of the U.N. Charter. International law is based on practical precedents, on the way given actions were legally judged by the world community in the past. It is a testament to the selective use of international law in the case of Israel that Morocco’s “Green March” into Western Sahara, by far the closest parallel to this week’s events, has not even been mentioned by world leaders.

Morocco was not deterred. Right after being rebuffed by those international organs, it mounted the Green March — sending 350,000 unarmed Moroccans on a well-choreographed hike into Western Sahara. Spain was not willing to fight against such numbers, and evacuated the territory. The Moroccan military moved in, and the territory remains under Moroccan control to this day.

The press has taken to calling the Arabs marching across the Israeli frontier “protesters.” In fact, “protests” are contained within a country; the organized crossing of a frontier is an invasion. In 1975, when Western Sahara was the victim, the world community was clear on this point (even though the Moroccans were unarmed, while the Syrians and Lebanese attacked Israeli soldiers with stones and other objects). Other Arab leaders called the Green March “a violation of the sovereignty of” Western Sahara and “an act contrary to international law.” Prominent international scholars described it as an illegal use of force, a “stealing of the Sahara,” in the words of one of the leading international lawyers of the time. The U.N. Security Council passed a measure that “deplored” Morocco’s invasion.

Moreover, despite the nominally civilian character of the marchers, several U.N. General Assembly resolutions recognized that the enterprise constituted a military occupation by Morocco. Observers noted that the march could not have gone off without the permission, and indeed encouragement, of King Hassan of Morocco, and thus he must take responsibility as if he had ordered army units across the border. It was a conquest despite the lack of arms: A large organized mob can be as forceful as an armed military unit. Indeed, as the Spanish capitulation proved, a march could be a more effective tool of conquest than a military strike against Western armies reluctant to fire on civilians.

Perhaps world leaders today would rather not remind anyone of the Moroccan occupation of Western Sahara, which in many ways showcases how the international rules applied to Israel are not those that govern the rest of the world. Rabat has occupied Western Sahara almost as long as Israel has occupied the West Bank, and with much less legal pedigree. Yet international efforts to end Morocco’s occupation have been scant and half-hearted. The occupation has been effectively accepted since the “peace process” in the region collapsed in 2004, when Morocco rejected a peace plan endorsed by the Security Council, with no damage to its international relations. Moreover, Morocco has implemented a massive policy of government-orchestrated settlement of Western Sahara. Yet the failed U.N. peace proposals did not contemplate uprooting a single Moroccan settler. Indeed, in the Security Council’s failed plan, the settlers, who now outnumber the natives, would get to vote in a plebiscite on the territory’s future.

Many observers have suggested that infiltrations represent a powerful new Arab tool for influencing world opinion against Israel. Yet the march tactic is not civil disobedience: It is an attempt at foreign conquest by the Arab states, just as when Morocco did it. Netanyahu has filed an official complaint with the Security Council. The United States, a permanent member, should press for action on it. If that body wished to demonstrate its impartiality, it would condemn Israel’s invaders as surely as it did Western Sahara’s.

— Eugene Kontorovich is a professor at Northwestern University School of Law. National Review