Diego Garcia: US and Allied Basing Rights in the Era of Great Power Competition

On June 24, 2020, CNA’s Strategy and Policy Analysis program hosted a virtual, on-the-record event to discuss the current and future status of Diego Garcia, an island in the Indian Ocean’s Chagos Archipelago that hosts a key US military base. This event built on a CNA event last summer that examined the intersection of sovereignty and US basing rights around the world. The Chagos Archipelago is currently administered by the United Kingdom, but Mauritius has a long-standing claim to sovereignty over the island chain that has been bolstered by international legal developments in recent years. The event featured Mauritius’ Permanent Representative to the United Nations, the Honorable Jagdish Koonjul, CNA’s senior vice president and general counsel, Mr. Mark Rosen, and Ms. Nilanthi Samaranayake, director of CNA’s Strategy and Policy Analysis program. Ambassador Koonjul read prepared remarks (attached as an appendix) elaborating Mauritius’ position that permits continued US military presence on Diego Garcia if sovereignty reverts to Mauritius. Panelists engaged in a frank discussion of the United States’ continued strategic needs, recent developments in the Mauritius-UK sovereignty dispute, and the future of the US base on a Mauritian Diego Garcia.

• Naval Support Facility Diego Garcia remains immensely valuable to the US’s diplomatic and military position amid great power competition. Sitting at the crossroads of the Indian Ocean, the base enables US military operations in both the Middle East and South and Southeast Asia. By enabling US military capacity, Diego Garcia serves a key role in reassuring and supporting both long-standing and new allies and partners in the Indo-Pacific region.
• Mauritius would permit a US base at Diego Garcia if the islands transfer from British to Mauritian control. Ambassador Koonjul stated that Mauritius would “favor the continued operation” of the US base at Diego Garcia if the Chagos Archipelago returns to Mauritian administration. Furthermore, he noted that Mauritius does not intend to resettle Chagossians on Diego Garcia itself, but rather on other islands in the archipelago.
• Backing a handover from the UK to Mauritius could reinforce US claims that it supports a rules-based international order. All three speakers noted that the dispute over the Chagos illustrates the potential influence of international legal actions in shaping an important US security arrangement. The UK has faced mounting diplomatic costs since the International Court of Justice’s (ICJ) 2019 advisory opinion.
• Long-term US access to Diego Garcia should not rely on economic benefits alone. If the archipelago comes under Mauritian control, the US should seek to provide more than simply economic benefits for Mauritius, such as security guarantees.
• The time appears ripe for a US realignment. Speakers argued that the United States’ long-term interest would best be served by working to find a solution that transfers Diego Garcia to Mauritian legal control but allows the UK to save face legally and politically.