The Strategic Utility of Diego Garcia

Ben Ho – Last month’s vote by the United Nations General Assembly to end Britain’s control of the Chagos archipelago in the Indian Ocean has cast a spotlight on the key American military base on Diego Garcia.

The non-binding vote was overwhelmingly in favour of the British Government, which rules the Chagos as a British Indian Ocean Territory, returning them to Mauritius. This came after a similarly non-binding International Court of Justice ruling in February that the Chagos was not legally separated from the Mauritius upon the latter’s independence from British colonial rule in 1965.

Diego Garcia is the largest of the Chagos, and Britain has leased the base on it to the Americans up to 2036. The atoll has supported various major operations in the Indian Ocean region in decades past, and its role as a key US military base will continue in the face of an uncertain regional security outlook. As the old axiom goes, ‘geography is destiny’, and Diego Garcia’s location is what makes it such a crucial node in Washington’s Indian Ocean strategy.

According to naval strategist Milan Vego, a professor at the Naval War College, Newport, Rhode Island, a “good… base should provide more than one line of operations,” because a “a base situated on an island or peninsula fronting the open sea usually offers multiple lines of operations.” This describes Diego Garcia exactly, as one can see that the northern approaches to the island, toward which friendly forces are likely to deploy, are entire open ocean and allow for greater freedom of action. Indeed, Diego Garcia is almost smack in the middle of the Indian Ocean, and is nearly equidistant between the restive ‘Arch of Crisis’ region as well as the south-east Asia littoral.

Past events show that Diego Garcia is the point d’appui for multiple lines of operations. Strategic bombers from its airstrip flew northwest to partake in Operations Desert Storm, Enduring Freedom and Iraqi Freedom. In recent years, counter-terrorism and anti-piracy operations in the Horn of Africa littoral also originated from the atoll. And last year, B-52 Stratofortress bombers took off from Diego Garcia to conduct ostensibly freedom-of-navigation missions in the South China Sea, which is east of the island.

Diego Garcia’s location is also noteworthy due to its isolation – the nearest landfall is over 1,600 kilometres away in India and it is some 3,500km away from a potential area of operations in the northern Arabian Sea. This state of affairs cuts both ways. Vego maintains that “a balance must be found between selecting a base that is close to the prospective theatre of operations and one that is further away but provides more security from enemy attack.”

In this regard, Diego Garcia is safe from most enemy fires, save for long-range weaponry like intermediate-range ballistic missiles, as well as sea-launched cruise missiles. On the other hand, the island’s remoteness afflicts it with the ‘tyranny of distance’. Only long-range aircraft such as strategic bombers can deploy from the island towards southern Eurasia without in-flight refuelling. In the same vein, any naval force deploying from Diego Garcia toward the same area would need a few days to reach their destination.

Another aspect of Diego Garcia’s geography is that it is the only US base in the Indian Ocean littoral where there are not as many issues pertaining to access compared to other bases. After all, it is leased from America’s staunchest ally, Britain, and its only inhabitants are military and civilian support personnel of these two nations – there are no locals whatsoever as they had been expelled in 1971. Indeed, local political sensitivities may hinder US access to their foreign bases in times of crisis. Think of Turkey’s refusal to allow US forces to deploy from its soil against Iraq in 2003. What is more, Diego Garcia is virtually immune to terrorist attacks.

Going forward, while prophesying is a fool’s errand in the capricious world of international politics, it is arguably safe to say that the US presence on Diego Garcia is unlikely to be affected in the short term at least. After all, the UN vote is symbolic and non-binding.

Moreover, even if Mauritius does regain control of the Chagos in the more distant future, it makes much financial sense for it to continue to lease Diego Garcia military base to an external power. The issue then is that this power could be someone other than the United States.

Beijing has been active in extending its influence in the Indian Ocean in recent years through the courting of regional states such as Sri Lanka and Pakistan with this trend set to continue. It is also worth noting that Mauritius signed on with the Belt-and-Road initiative last year. A Chinese foothold in the Chagos makes much strategic sense given that they flank the vital sea lines of communication between China and the oil-producing countries in the Persian Gulf, hence contributing to the security of these shipping routes.

by Ben Ho