Introduction

The geopolitical landscape and conceptions of the 16th century are still relevant in 21st-century geopolitical tensions. Hayrettin Barbarossa Pasha aforementioned that he, who ruled the sea, would soon rule over the land and trail the Ottoman Empire to contain strategic points in confide areas. The strategic chokepoints belittled the enemy's maneuverability, controlling the coastal regions for raiding and piracy. This strategy is being utilized by the U.S and China for surveillance, preventing the enemy from entering the sea shipping routes, and constraining each other’s presence globally. Similarly, during the 19th century, American strategist Alfred Thayer Mahan primed the orientation of naval ships of the USA, Germany, and Japan to rule the seas and the world. The power of the sea is still pushing the great powers- the U.S and China- on naval development, island seduction, and strategic dominance in the Indo-Pacific region.

The Seaman: A great geostrategic planner 

Whenever the West faced a rise or decline, sea power was the dominant factor reshaping the Western world order. During the 19th century, the decline of European powers in naval capacity became a cause of concern for the British military, economy, and political dominance worldwide. The tremendous economic recessions and domestic unrest of 1893-94 pushed Americans outward and built a stronger frontier. Mahan and Frederick Jackson Turner analyzed that only a strong navy could get better of the American people's social, economic, and political obstacles. Mahan spearheaded sea power, inspecting it as essential for American global, financial, and political dominance. He supported the argument of building the most substantial number of commercial and merchant ships to rule the waves and overhaul the international trade system.

For the Mahanian school of thought, island states and canals are strategic nodes in pulling the strings of global power dynamics due to their maritime positioning. Mahan, therefore, reinforced the idea of securing strategic canals and small islands to build up the network of coalition and refueling stations to secure sea lanes of communication and for the American presence at these strategic nodes, which would leverage the American influence in the future. He advocated the policy of the Trinity: National wealth, commercial power, and naval military power, which is a geo-economics companion to Clausewitz’s geopolitically inflected trinity of people, government, and military power. He was instrumental in shaping the idea that “economic policy is the national security policy”, and the control of these canals and small islands in the hands of an adversary is the biggest threat to the American national interests and global influence.

Diego Garcia: A strategic node of the new Cold War

As Mahan mentioned, controlling the Panama Canal, Hawaii, and the Caribbean Sea was essential for expanding American influence on the European continent. Diego Garcia's position in the Indian Ocean region is pivotal for expanding American influence in Asia, ‘a tip of the spear’ to deter adversaries, and maintaining its credibility for the global alliances. The Chagos archipelago, a British Indian Ocean Territory (BIOT), was used since the Cold War for military purposes to defend the interests of the UK and its allies, lies northeast of Mauritius, south of the southern tip of the Indian subcontinent, and comprises more than 60 islands. Diego Garcia, an atoll, is one of the largest islands of 52 hosting a joint military base of the UK and the U.S.  It holds one of the most strategic deep ports of the U.S with the capacity of a long runway, berthing aircraft carriers, facilitation of command and control for deep strikes and military operations in Middle East and a pivotal strategic node for the logistics support, refueling, reconnaissance, surveillance and credible deterrence to deter the regional adversaries.

Diego Garcia has proven a real-time “trinity “for the US amidst shifting regional and global power dynamics and stabilizing the national and international security. It previously worked as a geo-economic hub for commercial ships, a geostrategic node to contain the influence of the ideological adversary—the bear—enhanced the credibility of the American regime for alliances, and empowered democratic governments in the Middle East, South, and Southeast Asian regions. It has been instrumental in projecting the American power and interventionist strategies during Iran’s Islamic revolution, the wars in Iraq and Kuwait, and the war on terror, the invasion of Afghanistan, Operation Desert Fox, Operation Enduring Freedom, and strikes on the Houthis till now. As the Houthis have procured modern equipment and pose an existential threat to the US naval ships and disrupt the energy supplies, the US has launched relentless strikes on the Yemeni Houthis to showcase its power. The US relied on the military base at Diego Garcia to conduct and deploy six B-2 stealth bombers, a C-17 military transport aircraft, and several KC-135 refueling tankers, which reflects the US intentions to continue the containment of the fierce chain led by Iran, China, and Russia, and continuity of grand American strategy.

Mauritius-UK deal and Diego Garcia sovereignty

Historically, Diego Garcia was under Mauritius's control until France colonized it in 1769 and Great Britain in 1814.  After the independence of Mauritius in 1968, Diego Garcia remained under the colonial rule of the UK and part of its 14 overseas territories for defense. The island was leased for 55 years to the US by the British in exchange for a discount of $14 million on sales of the Polaris missile system, a key strategic location for the US to contain the USSR in the Middle East, Southeast Asia, and South Asia.  An agreement between the UK and Mauritius was reached in 2024, handing over the Chagos Islands to the Mauritian government, except for Diego Garcia, which is leased for the next 99 years and might extend 40 years. After the reckless two-year negotiation over the sovereign rights of the Chagos Archipelago, the UK government has granted sovereign rights to the Mauritian government over the Chagos Archipelago, including Diego Garcia. Now the Mauritian government will be able to resettle the Chagossian people in the Chagos archipelago, except Diego Garcia, for which the UK government will establish trust funds for the Chagossian and sign agreements on environmental protection of the archipelago. On April 1, 2025, the UK government announced that it would finalize the deal without the final affirmations of Donald Trump despite massive criticism from the conservative party.

Diego Garcia dilemma  

The decolonization of the Chagos Islands and China's growing interest in Mauritius and the Chagos Islands have created serious security concerns, opening doors of opportunity and competition for the US strategic posture in the Indian Ocean and the Arabian Sea.  Under the free and open Indo-Pacific strategy, the Biden administration welcomed the agreement and opened doors for strategic partner India to grow regional influence. However, Mark Rubio, the newly elected secretary of state, signaled to torpedo the deal for the US national interests in the world's most crucial island for America. Strategic nodes such as the Gulf of Mexico, Greenland, and Diego Garcia embody Mahan’s strategy for the trump administration and the sake of American interests. Therefore, the trump administration views this deal with great hostility and has indicated that it will terminate the agreement.

Navigating the way ahead

The Trump administration has two ways to resolve this strategic dilemma. First, it can accept the sovereignty of the Chagos Islands and use the Diego Garcia military base for the next century to contain China and empower India in the region. The case seems challenging to get the Trump administration's acceptance due to its strategic focus on islands worldwide, which gives American forces strategic leverage. What might be the option for the US if the UK cedes the sovereignty of the Chagos Islands to Mauritius? It might be the case that the US prevents Chinese access to the Chagos Archipelago, and if it violates, it would consider the act of war with the US. It might be possible for the US to weaponise the allies in the Indian Ocean, such as India. India has strong historic ethnic and cultural ties with Mauritius, and 60% of the Mauritius population is of Indian descent. Moreover, the Indian Navy has been commanding the Mauritius coastal guard forces and facilitated numerous surveillance operations along with the Mauritius police, which reflects its ambitions under the Sagar policy to deepen its strategic relations with the island nations. In addition, India has been in a continuous struggle to build a military base in Seychelles, which exemplifies its commitment to the necklace of diamonds strategy.  Thus, the US should empower the Indian ambitions to strengthen the Quad alliances and set the conditions for the Mauritian government to establish an Indian military base in Mauritius or near the Chagos Islands to overcome security threats to the US and its allies' interests and prevent the spread in the Indian Ocean region.

Second, if it torpedoes the agreement and challenges the international order of norms and free access to the Indo-Pacific, it would eventually favor China, tending Mauritius towards China due to its sovereign rights and strategic realignment. It might be possible to show outrage to the U.S, Mauritius becomes a military base for the Chinese, like its neighbours. As 54 out of 55 states come under the Belt and Road Initiative (BRI), Mauritius was the first African country to sign a free trade agreement with China. In addition, China is Mauritius's second-largest import partner, and Mauritius' exports to China have increased by up to 70%, including fish and fish products. The independence of the Chagos archipelago, a hub of unique kinds of fish, will boost the China-Mauritius cooperation opportunities and open a window for the Chinese fish vessels to play freely in the Chagos archipelago. The Chinese fish vessels are already operating in the surrounding waters of Seychelles, Mauritius, Madagascar, and Djibouti. At the same time, access to the Chagos Islands would provide a strategic node to move in the crossroad of the Indian Ocean to facilitate its surveillance and information gathering networks to increase the credibility of its strategy, ‘strings of pearl’ strategy.

Conclusion

 While summing the argument, the second case would mark ripple effects on US credibility and the disarray of its allies. It would make better space for China to cement its foot in the Chagos Islands. Thus, the Chagos Archipelago has become a new flashpoint, similar to the Taiwan Strait in the Indian Ocean region, where geopolitical rivals will compete for greater influence in this new strategic containment environment. Therefore, the island's dilemma requires a more robust and a compromise strategy to maintain the US and its allies’ interests alive in the Indian Ocean region and empower the credibility of the US deterrence posture.

Ehtasham Ali is an independent researcher at the University of the Punjab, Lahore. He has worked as a research assistant for DAI and Global Defense Insight. His areas of interest include arms control, emerging technologies, and international security. His previous work was published on the Strafasia, Stratheia, and the Asian Politico.