Is Diego Garcia at Risk of Slipping from Washington's Grasp?

September 19, 2017 Topic: Security Region: Asia Tags: PentagonMilitaryWarU.S. NavyWeaponsTechnology

Is Diego Garcia at Risk of Slipping from Washington's Grasp?

Diego Garcia’s strategic importance cannot be overstated because the Defense Department has, in general, been gradually reducing its overseas presence throughout the world.

On June 22, 2017, the UN General Assembly voted 94-15 (sixty-five abstentions) to ask the International Court of Justice to issue an advisory opinion on whether the UK had lawfully adhered to the process of decolonization when it detached the Chagos Archipelago from Mauritius in the 1960s. U.S. newspapers mostly ignored this news; hopefully Pentagon planners took note. The timing of this action—which could be viewed as delegitimating the U.S. presence on Diego Garcia, the largest island in the Chagos Archipelago—is not good for the United States. The country has been deepening its defense relations with India and devoting more strategic attention to the Indian Ocean from a security and economic perspective. Approximately 70 percent of the world’s crude oil and 50 percent of the world’s container traffic moves through the Indian Ocean.

The U.S. facility on the island of Diego Garcia is the strategic anchor for the U.S. defense presence in South Asia, the Middle East, and the Pacific region, according to Andrew Erickson from the Naval War College. Diego Garcia could not be more strategically placed because of its unique geography and its relative isolation to areas of conflict. Since 1966, the island has been a secure venue for a number of very important U.S. defense activities.

Technically an atoll, Diego Garcia is under British administrative control. It has an area of roughly sixty-five square miles, yet it offers protected anchorage to U.S. Defense Department maritime prepositioning vessels, repair vessels, refueling facilities and two parallel twelve-thousand-foot runways capable of handling long-range aircraft. The naval base piers are capable of handling U.S. aircraft carriers as well as smaller ships. The location enables long-range bombers, for example, to strike targets in Afghanistan, North Africa, the Persian Gulf and Red Sea, most of Southeast Asia and the Taiwan Strait and return to safety. It is also a safe place for resupply, rearming and repair of submarines and other Navy ships. It has been homeport (and frequent visitor) of deep-draft submarine tenders.

Diego Garcia’s strategic importance cannot be overstated because the Defense Department has, in general, been gradually reducing its overseas presence throughout the world. The U.S. Navy’s Naval Communication Station Harold E. Holt (in western Australia) has provided some rough equivalence in terms of location, isolation, expandability and a friendly host government, but the U.S. Navy left its communication and pier facilities in the mid 1990s. Some contract operations remain but the base has been significantly scaled back from what it once was. With the possible exception of the Defense Department’s presence in Djibouti on the Gulf of Aden (which has access to an airhead and port facilities), there are no facilities on the West Coast of Africa or offshore capable of logistically or politically providing the same sort of base to safely sustain and launch combat operations in multiple theaters of operation. Those who argue that the Defense Department can gain access to suitable replacement facilities underestimate the difficulty it has obtaining access to a foreign territory where it can conduct freedom-to-launch offensive operations, expand facilities or bring in whatever military equipment is necessary to meet operational demands.

History and Legal Basis for the U.S. Presence

Diego Garcia owes its name to a Portuguese navigator who discovered the uninhabited atoll in 1532. The modern history begins in the late eighteenth century, which is when slaves from Africa settled on the archipelago to work on Franco-Mauritian coconut plantations. France administered the archipelago as a dependency known as Ile de France until the British captured the territory in 1812 and renamed it Mauritius. France ceded its rights in 1814 to Great Britain, which has administered it ever since first as a Dependency of Mauritius and later as the British Indian Ocean Territory. The freed slaves and indentured laborers from India lived together as a diverse mix of peoples with their own language, Chagos Kreol. The population was mostly involved in the production of coconut oil.

“That beautiful atoll of Diego Garcia, right in the middle of the ocean,” is how Stuart Barber described the island in the late 1950s. A civilian working for the U.S. Navy, Barber recognized that the location of the island was ideal as a logistics base and for contingency operations in the Indian Ocean and elsewhere. Diego Garcia offered great security benefits since there were few—if any—local inhabitants to protest the military presence and the remote location made it inaccessible to outsiders who might come by boat to disrupt operations. Presidents Kennedy and Johnson pressed the UK for rights to a shared facility on the island and commenced negotiations to “detach” the entire Chagos Archipelago from Mauritius. Since the UK’s Indian Ocean territories were approaching independence, London sought complete detachment of the Chagos; however, the colonial representatives of Mauritius pushed for a lease arrangement in which Mauritius would retain rights to access the Archipelago’s waters for fishing, oil and gas, and emergency landing. Mauritius and the UK agreed to let Mauritius obtain emergency landing and resource rights, but they also reportedly agreed to the UK retaining sovereignty and making Diego Garcia available to the U.S. military. Mauritius received a cash payment to relinquish its claim; however, sources differ on the actual amount received—between $3 million and $8.4 million.

The U.S. presence on Diego Garcia is based on a long-term lease with the United Kingdom. The original fifty-year lease commenced in 1966 and expired in 2016. It was a no-cost lease except that the United States did reportedly waive certain costs associated with the UK’s purchase of sea-launched ballistic missiles from the United States. The two countries agreed on the original lease two years before Mauritius was granted independence from the UK in 1968.

At the time of the detachment of the Chagos from colonial Mauritius in 1965, there were, according to the Arbitration records, roughly 1,500 people living on Diego Garcia. Both the UK and United States believed that the copra plantations on Diego Garcia and the three other islands had to be closed and the islanders were driven out and settled in Mauritius and Seychelles. The UK government paid an initial sum of $650,000 pounds for resettlement costs and agreed to establish a resettlement fund of $4 million pounds to pay for the long-term needs of the former residents.

What Has Changed?

Much to the chagrin of those who were displaced by the UK to make way for the U.S. base and others who wanted a say on the matter, the UK extended the U.S. lease to Diego Garcia from 2016 to 2036. As a practical matter, so long as the United States sits on the island, Chagossians are practically precluded from returning because of the way that the lease is interpreted.

Renewal of the lease is not the only contentious issue. In 1998, the former Chagos residents sought judicial review of their expulsion in the UK courts. They both sought return rights and compensation for being unlawfully ejected. In 2000, a divisional court in the UK ruled that the ordinance expelling the Chagossians was unlawful. Based on this decision, the UK government conducted a study which, in essence, concluded that the return of the Chagossians would be cost prohibitive and living conditions were not suitable. The results of this study were contested in subsequent legal actions.

The Chagossians who emigrated to the UK, gained British citizenship in 2002 and now have a one-thousand-strong community in Sussex. They are still seeking to return home and have become symbols of the victims of big-power politics. Their story is told in A Few Man Fridays, a play written and directed by Adrian Jackson, an artistic director who makes theater championing the displaced and homeless. Even though public opinion in the UK views the Chagossian episode with great sympathy, the UK Supreme Court still dismissed the case by Chagos islanders who sought damages and reinstatement rights in June of 2016.

The UK and, by extension, the United States were separately confronted by the Mauritius government in an international arbitration convened pursuant to the UN Law of the Sea Convention (UNCLOS). Mauritius sought to enforce terms of their agreement with the UK when Diego Garcia was “detached” from Mauritius to create a pathway for a Chagossian return to the island. That so-called “Lancaster House” agreement of 1965 promised that the Chagos Archipelago waters would be available to Mauritius for fishing and other economic activities, including mineral and oil prospecting, but did not envision any extraction licenses being issued. Contemporaneous diplomatic communications between Mauritian authorities and the UK indicate that the UK would retain sovereignty over the islands. But retention of sovereignty was conditioned on a commitment that the islands would be returned to Mauritius when the territories were no longer needed for defense purposes (in the sole discretion of the UK).

In the arbitration, Mauritius specially challenged the UK’s declaration of a marine-protected area (MPA) off all waters around the Chagos because the UK did this without first consulting Mauritius. The practical effect of the MPA is that waters around Diego Garcia would become off limits; especially to fishing inside of the two hundred nautical miles exclusive economic zone that surrounds the Chagos islands. Mauritius argued that it had resource rights to the waters and the MPA affected those rights. Therefore, the UK could not take such actions unilaterally.

The Law of the Sea Arbitral Tribunal Ruling

The tribunal ultimately found in Mauritius’ favor since the original agreements detaching the Chagos from the Mauritius territorial area recognized Mauritius’ rights to exploit the economic resources in the exclusive economic zone of the Chagos Islands and the continental shelf. Given that agreement, Great Britain was “stopped” from taking any action that would compromise Mauritius’ legal rights to fish in those waters. The tribunal also went a step further to chastise the UK for its assertion of sovereignty even though Mauritius has been fishing in the waters for many years.

The tribunal declined to rule on the question of whether the extension of the lease was appropriate (because the Lancaster House Agreement didn’t explicitly state that the rights to retain the Chagos Islands was dependent on the UK’s need to use it for defense purposes), but it did suggest that the promulgation of a MPA to prevent Mauritius from being able to pursue its claims was an action that was not taken in good faith—reinforced because of some leaked “WikiLeaks” diplomatic cables, which suggested that the MPA was established to prevent anyone from returning.

The UN General Assembly and the World Court

The UK’s problem didn’t end with the arbitration. As noted in the introduction, Mauritius pressed its claim to reclaim sovereignty over the Chagos Islands in the UN General Assembly (UNGA). It took this action at the UNGA because any action in the Security Council would be subject to veto by either the United States or Great Britain. It is interesting, from a legal perspective, that Mauritius took this particular approach (even though they are represented by skilled U.S. counsel) since the Permanent Court of Arbitration panel made findings that the collection of “Lancaster House” undertakings were “international obligations” and the Lancaster agreement suggests that in exchange for the UK’s various concessions that the “decision on the need to retain the islands must rest entirely with the United Kingdom Government and it would not (repeat not) be open to the Government of Mauritius to raise the matter or press for the return of the islands on its own initiative.” It will be interesting whether the International Court of Justice applies the same estoppel arguments to Mauritius that it did to the United Kingdom in the arbitration case. It is unlikely that the court will deterred by the actual language in the Lancaster House agreements because of the growing body of international law and policy, which favors the self-determination rights of former colonies and indigenous residents over their former colonial rulers.

What’s Next?

The problem isn’t the lease between the United States and the UK. It’s the landlord. Or more precisely, will the UK continue to be the landlord or will it be legally or politically pressured via an adverse court decision to divest the vestiges of its colonial holdings?

International Court of Justice advisory opinions are not legally binding; however, if there was a verdict in favor of Mauritius, then that would put a lot of pressure on the UK to cede its rights to the Chagos Islands. At the very least, it would put pressure on the United States and the UK to negotiate a new basing agreement with the United States in which Mauritius has a greater say in the terms of U.S. basing arrangement or the types of things that occur on the base.    Mauritius would undoubtedly assert return rights (or some suitable substitute arrangements) on behalf of the Chagossians that still remain in Mauritius following their removal from the islands in 1973. The UK and United States both believed that Indian government could play a constructive role in getting Mauritius to tread carefully and asked for help; however, the Indian representative to the UN supported the UNGA resolution as a “matter of principle for India to uphold the process of decolonization and the respect for sovereignty of nations.” Given that India has been actively increasing military ties with the United States mostly because of concerns with China and signed a ten-year defense framework agreement, it is curious that India insisted on voting against the UK, and by extension, the U.S. presence in Diego Garcia. Should India ever require U.S. military assistance in the India Ocean, some portion of that support would likely come from the island.

Mauritius certainly has a strong economic reason to reacquire the sixty square kilometers of the Chagos Islands as part of greater Mauritius since it is surrounded by thousands of square kilometers of coral reefs and the British Indian Ocean Territory exclusive economic zone for management of marine resources, (in the water column and seabed) which is roughly six hundred thousand square kilometers—more than twice the total UK land area. This marine space includes mid-ocean ridges, trenches and abyssal plains, as well as coral reefs, atolls and banks. It contains one of the few undamaged Indian Ocean coral reefs and its coral reef fisheries are more abundant than in other Indian Ocean locations; however, there is considerable poaching of turtles, sharks, sea cucumbers and other marine life. No data could be found on whether the seabed areas in and around (up to two hundred nautical miles seaward) the archipelago, contain hydrocarbon or other mineral resources. The archipelago’s isolation, unique history as a coconut-oil plantation, and closed military area, all militate against the possibility that there has been active prospecting. Given that, Mauritius is probably eager to learn whether the waters near the Chagos Islands have oil and gas that it can exploit.


It is very unclear if policy officials in the United States are heavily focusing on the recent legal and political events that have occurred in three separate venues: the UK courts, the Permanent Court of Arbitration, and now the UN General Assembly. When viewed in isolation, these problems are manageable; but, when put into a larger context of possible Mauritian territorial ambitions, it is clear that the United States and the UK will need to redouble their efforts to deal with the issue of displaced Chagossians and the economic aspirations of Mauritius. The United States arguably has more to lose in this battle over sovereignty and it would do well to help try and craft a solution that puts it on the right side of this issue because Diego Garcia is irreplaceable real estate. Helping to resettle the displaced Chagossians on their ancestral lands and providing economic incentives to Mauritius—such as unrestricted fishing and mineral rights—may be what is necessary for the United States to retain its ability to operate freely from the island. Also, convincing India that it should respond positively to U.S. and UK overtures to Mauritius would appear to be in India’s best interests if it wants a more robust defense relationship with Washington.

Mark Rosen is the senior vice president and general counsel at CNA. This article represents his personal views. None of the opinions expressed herein should be taken as the opinion of CNA or any of its sponsors.

Image: A B-1 Lancer prepares to connect with a KC-135 Stratotanker refueling boom over the Indian Ocean on July 7. The B-1 was flying a close-air-support mission in support of Operation Enduring Freedom. Wikimedia Commons.


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