A small Yemeni island was recently at the center of a little-noticed standoff between three states—Yemen, the United Arab Emirates (UAE), and Saudi Arabia. The dispute reveals the tenuous hold the Yemeni government has over its own territory. The events—and collective shrug the world offered in response—also offer worrisome signs that the norm of territorial sovereignty may be weakening, at least in this conflict-ridden nation. This island dispute presents the possibility that the war raging in Yemen has quietly slipped into a violation of the UN Charter. That possibility, in turn, re-raises legal concerns regarding U.S. support for the Saudi-led coalition’s actions in Yemen.

The island at the center of the scuffle is Socotra, not quite 1500 square miles of land with 60,000 residents located at the entrance to the Gulf of Aden. The island is Yemeni, but it has been largely spared from the violence brought by the civil war that has ravaged much of the rest of the country since March 2015.

Though spared from war, Socotra was hit by cyclones in November 2015. Mainland Yemen, paralyzed by war, was in no position to provide assistance, so the UAE stepped in to send aid flights and assist in rebuilding efforts. The UAE, a central member of the Saudi-led coalition supporting Yemen’s government against the main rebel group, the Houthis, took the opportunity to quietly establish a military presence and training course on Socotra while investing in a number of infrastructure development projects.

In 2016, unconfirmed rumors began circulating that Yemen’s President Hadi (who remains in exile in Saudi Arabia) had signed a 99-year lease with the UAE. The situation was exacerbated when Hadi was refused landing permission at the UAE-controlled airport in Aden in February 2017.  In May 2017, Hadi accused the UAE of behaving “like an occupation power in Yemen.” Relations were further strained by UAE support for the Southern Transitional Council, a group that formed in May 2017 and seized the city of Aden from Hadi’s government in January 2018. Two UK journalists who visited Socotra in April 2018 reported that the UAE had “all but annexed” the island and that there were rumors of plans to hold a Crimea-style referendum to secede from Yemen and become part of the UAE.

Tensions ratcheted up even further last month.  On April 30, 2018, four UAE military aircraft landed on Socotra carrying at least 100 soldiers and two tanks. Shortly thereafter, UAE forces seized the seaport and airport. The move took place during a visit to the island by Yemeni Prime Minister Ahmed Obeid bin Daghr, who was reportedly blocked from leaving the island by UAE forces. Protests broke out on the island, and Saudi Arabia sent in a negotiating team, followed by its own military forces, purportedly to conduct a joint training mission. The three sides announced they had reached an agreement on May 14 to commence a phased withdrawal of UAE forces from Socotra. Prime Minister Daghr announced that the crisis was over and that Yemen’s flag was “flying above our sea and airports again.”

This clash raises serious questions about President Hadi’s control over Yemen.  As we discussed in an earlier article, Yemen’s consent is essential to the legality of the use of force by the Saudi-led coalition in Yemen—and U.S. support for it.  Article 2(4) of the UN Charter prohibits the “threat or use of force against the territorial integrity or political independence of any state,” but a state may consent to the use of force. However, that consent is limited to “particular conduct by another State . . . to the extent that the conduct remains within the limits of the consent given” (Draft Articles on State Responsibility, art. 20).

President Hadi requested assistance from the UAE in his fight against the Houthis on March 24, 2015, thereby giving them permission to operate within Yemen’s territory. Hadi can revoke this permission at any time.  The contest over Socotra and Hadi’s reference to the UAE as “occupiers” raises questions about whether his initial consent covers the UAE’s full range of activities in Yemen. (Not to mention the broader concern about the ongoing validity of Hadi’s consent to the actions of the Saudi-led coalition, given that he is under house arrest in Riyadh.) The uncoordinated addition of UAE troops in Socotra and the seizure of Socotra’s key transportation facilities appear to fall far outside the scope of the Yemeni government’s consent and, if proven, would be a brazen violation of Article 2(4) (and, therefore, a crime of aggression—though not one that could be prosecuted in the International Criminal Court, because none of the states involved are parties to the Rome Statute). That Hadi’s government has to negotiate with the UAE—with Saudi Arabia serving as an intermediary—to secure its own territory shows how weak the norm of territorial sovereignty is in Yemen.

Moreover, if the rumors are true that the UAE was pushing for a referendum for Socotra to secede from Yemen and become part of the UAE, that would be plainly illegal—and very bad for the international norm of territorial sovereignty. Unilateral secession is illegal under international law, even if supported by the population of the seceding territory.  That is all the more true when the plan is for that seceding territory to join another state.  The collective international shrug in response to the rumors that UAE was flirting with following Russia’s example in Socotra is cause for serious concern.

Last, these recent developments re-raise legal concerns surrounding continuing U.S. support for the Saudi-led coalition.  First, the willingness of the UAE to carry out such provocative actions in Socotra raises questions about possible U.S. legal obligations under the U.S. Arms Export Control Act (AECA). As we discussed in an earlier article about arms sales to Saudi Arabia, the AECA establishes restrictions on how military assistance may be used. It may only be used (1) “for internal security”; (2) “for legitimate self-defense”; (3) for stopping WMD proliferation; (4) for participation in regional or collective security arrangements that are consistent with the UN Charter; and (5) public works projects in developing countries. If the President or Congress determines that a recipient country is using its military assistance for any purpose other than one listed in the AECA, then the United States must terminate all credits, guarantees, and sales to that country. Here, if the UAE is using U.S.-provided military resources to commit aggression and violate the UN Charter, then the United States may be obligated to halt arms sales to the UAE.

Second, if the UAE were to violate Article 2(4), that could trigger U.S. legal responsibility under the International Law Commission’s Article 16 of the Draft Articles of State Responsibility. As we explained in an earlier article, Article 16 provides that “A State which aids or assists another State in the commission of an internationally wrongful act by the latter is internationally responsible for doing so if: (a) that State does so with knowledge of the circumstances of the internationally wrongful act; and (b) the act would be internationally wrongful if committed by that State.”  If the U.S. knowingly assists the UAE in a violation of Article 2(4) (by, for example, continuing to provide arms and other support), that would very likely make the U.S. legally responsible for aiding and assisting the UAE’s internationally wrongful act.

For now, the confrontation between Yemen and the UAE seems to have abated and, as a result, the legal concerns raised here have receded—for now. Recent reports suggest, however, that Yemen may be subject to similar pressure from Saudi Arabia. As a local official put it, “[A]lthough the UAE troops may leave, we may then suffer at the hands of the Saudi forces.” Thus the dangers to Yemen—and to the international legal order—remain.