The Indian Ocean is an overlooked theatre for nuclear escalation and conflict. Since the start of this year alone, Iran has threatened to strike a US military base in the Chagos Archipelago, China conducted live-fire drills off the coast of Australia, and India and Pakistan faced a sudden escalation in boundary tensions that extended into the maritime space. If not carefully managed, these military standoffs could escalate into wider nuclear conflict. Despite being home to six nuclear-armed or near-nuclear states, five maritime chokepoints, four Nuclear Weapons Free Zones, and 12 sovereignty disputes, the Indian Ocean remains understudied in nuclear discourse.
Current studies analyse the Indian Ocean according to its various sub-regions: East Africa, the Middle East, South Asia, Southeast Asia, etc. This compartmentalisation blinds policy makers to the region’s nuclear risks and escalation dynamics. Reframing the region as one continuous maritime theatre would give policymakers a new way to anticipate and manage these threats in the future.
Diego Garcia: the base at the centre of escalation. Take the recent escalations between Iran and the United States, for example. The United States has one military base in the Indian Ocean, on the island of Diego Garcia in the Chagos Archipelago. This base has historically been used for “deterrence missions” against Iran. In March, Washington increased deployments to Diego Garcia as part of a campaign of signalling and deception leading up to the US strikes on Iran’s nuclear facilities in June. The surge of force included B-52 and B-2 bombers, KC-135 tankers, and C-17 transports. Although the US attack on Iran ultimately did not originate from Diego Garcia, the island served as a decoy to distract from the impending attack.
In response to early threats from the United States, the Iranian government warned it would attack the Indian Ocean base with ballistic missiles and drones. To date, however, Tehran has only retaliated by limiting inspections from the International Atomic Energy Agency. On August 28, Britain, France, and Germany declared Iran in “significant non-performance” of the Iran nuclear deal, triggering a 30-day countdown for “snapback” sanctions to be imposed. Experts warn these sanctions could spark uncontrolled retaliation from Tehran. As tensions remain high, any military standoffs run the risk of escalating into the Indian Ocean region.
An escalation in the Chagos Archipelago would necessarily draw the United Kingdom into the mix. The Diego Garcia military base is jointly owned and operated by the United States and the United Kingdom, which retains ultimate authority over the facility. A strike on Diego Garcia—even if aimed at American forces—would also be a strike on Britain. Today, London maintains a declared nuclear posture that includes the deployment of submarines equipped with Trident nuclear missiles. The British posture of “deliberate ambiguity” about its nuclear red lines further complicates these escalation dynamics.
Decolonisation meets deterrence: the Chagos sovereignty dilemma. For decades, Chagos has also been the subject of a low-profile, high-stakes sovereignty dispute between Mauritius and the United Kingdom related to decolonisation and forced removal. When the African Nuclear Weapons Free Zone was established in 1996, the Chagos military base presented a major challenge to the treaty’s full realisation. While nuclear-weapon states like the United Kingdom, the United States, and France agreed that the “British Indian Ocean Territory” was exempt from the treaty, all participating African states argued that Chagos was part of Africa and should be covered by the treaty.
Today, the Chagos Archipelago is undergoing a sovereignty transfer from the United Kingdom to Mauritius. As the archipelago’s legal status evolves, so too does its nuclear status. Noting the significance of the base on Diego Garcia, Mauritius has offered a 99-year lease on the island in exchange for full sovereignty over the Chagos Archipelago. This deal includes an explicit commitment that Mauritius “would permit the unhindered operation of the defence facility [by the United States and the United Kingdom], in accordance with international law.” The phrase “in accordance with international law,” however, revives outstanding questions about whether Diego Garcia is included in the African treaty. While the terms of the deal have not been finalised, the general parameters raise a significant challenge to the African Nuclear Weapons Free Zone Treaty. If the Chagos Archipelago is now part of Mauritius’ sovereign territory, the United States and the United Kingdom could face increasing challenges to their ability to station, dock, or launch nuclear weapons from Diego Garcia.
If the United States continues to pursue deterrence through escalation with Tehran, the nuclear capabilities of Diego Garcia will increasingly come into question. Even if the United States and the United Kingdom manage to retain treaty loopholes, a perceived violation of the African Nuclear Weapons Free Zone may be treated as seriously as a legitimate one, especially in an escalation scenario.
An escalation over Diego Garcia could also extend to Australia. In 2021, the United States, the United Kingdom, and Australia established the trilateral security pact known as AUKUS. The centrepiece of AUKUS is the provision of nuclear-powered attack submarines to Australia, making it only the second non-nuclear-weapon state to operate such vessels. While these submarines are conventionally armed, they are powered by highly enriched uranium, raising nonproliferation concerns. If future AUKUS submarines operate out of Diego Garcia or use its facilities for logistics or surveillance, that might heighten perceptions of the base as a node of strategic nuclear power.
China’s shadow in the Indian Ocean. The US Indo-Pacific Strategy has also drawn China into the Diego Garcia equation. In February, China conducted live-fire naval drills off the southeast coast of Australia. Although this was not a direct response to AUKUS, China has been a strong critic of the security pact, accusing the partnership of fueling an arms race, undermining regional stability, and promoting nuclear proliferation. Put simply, Beijing sees AUKUS as a direct challenge to its interests in the Indo-Pacific region. Over the past few years, Chinese submarines (both conventional and nuclear-powered) have become more active in the Indian Ocean. Their patrols reflect broader trends of Chinese naval expansion and pushback against perceived Western containment in the region. This growing presence poses a direct challenge to the US military footprint in Diego Garcia, which is positioned to counter Chinese influence.
Today, Diego Garcia sits at the heart of an African sovereignty dispute related to decolonisation and nuclear non-proliferation. It is both a target and a node in the US military strategy in the Middle East, and a key part of the US Indo-Pacific strategy regarding China. In isolation, these seem like separate issues. However, further analysis reveals that they are deeply interconnected. The unresolved sovereignty dispute shapes perceptions of legitimacy, which in turn affects how adversaries like Iran and China respond to deterrence from the United States and the United Kingdom. At the same time, China’s growing activity in the region amplifies the strategic weight of the Diego Garcia dispute. Diego Garcia illustrates the way these regional conflicts are embedded in a wider nuclear order. The same dynamic can be seen in South Asia, where the India-Pakistan rivalry increasingly spills into the Indian Ocean.
South Asia at sea. This year, India and Pakistan faced a major escalation over disputed territory in Kashmir. Over the past decade, both India and Pakistan have made moves toward naval nuclearisation, creating an environment where even minor incidents at sea could spark strategic-level misunderstandings or escalations. Similar to the Diego Garcia situation, escalations between India and Pakistan are not contained to just these two countries.
India’s new doctrine of “maritime deterrence” is explicitly aimed at dissuading both Pakistan and China from provocative naval actions. Today, China’s submarines regularly conduct what Beijing describes as anti-piracy operations in the region. In an attempt to counterbalance China’s perceived expansion, India has increased its participation in the Quadrilateral Security Dialogue (a multilateral coalition between the United States, India, Australia, and Japan) and AUKUS-adjacent initiatives. India’s Indo-Pacific partnerships are increasingly viewed by China and Pakistan as encirclement, creating a spiral of mutual suspicion among all three states.
South Asian deterrence is also linked to security in the Gulf. During the 1970s and 80s, Pakistan received financing and support from Saudi Arabia to develop its nuclear weapons program, an arrangement that some believe could provide Riyadh with a latent nuclear option. In 2023, China brokered a détente between Iran and Saudi Arabia, raising hopes for regional de-escalation. In recent months, Iran has appealed to Pakistan for support in its own nuclear developments. The China-Pakistan axis, Saudi-Pakistani security ties, and tenuous Pakistan-Iran relationship further complicate the regional security environment. Any conflict involving Iran could potentially engage Pakistani, Chinese, or even Saudi interests, further tethering Middle Eastern volatility to South Asian nuclear dynamics and Indo-Pacific rivalries.
France and Russia in the Indian Ocean order. There are two other nuclear powers in the Indian Ocean: France and Russia. France maintains a lasting presence in the Indian Ocean through its territories like La Réunion and Mayotte. About 7,000 French military personnel operate under the Forces Armées de la Zone Sud de l’OcéanIndien, conducting surveillance, counter-piracy, disaster response, and deterrence missions. French submarines also patrol the region as part of Paris’s continuous at-sea nuclear posture.
Although Russia does not have overseas territories in the Indian Ocean, it has continued to pursue naval access agreements with countries such as Sudan, Madagascar, Mozambique, and the Seychelles. Russia also conducts joint naval exercises with China, Iran, and India, and occasionally deploys nuclear-capable submarines through the Indian Ocean as part of its global deterrence posture.
Seeing the whole ocean: rethinking nuclear risks beyond borders. The Indian Ocean is no longer a peripheral space in nuclear politics. It is a central arena where regional conflicts, great-power rivalries, and nuclear deterrence increasingly intersect. Yet policymakers still view it through fragmented regional lenses that obscure the risks of escalation. From Diego Garcia to India-Pakistan, these situations overlap in ways that increase the likelihood of miscommunication and miscalculation. In March, for example, the United States sent B-52 bombers on a deterrence mission that was aimed at Iran, the Houthis, and China. What happens when communication lines get crossed? As more nuclear powers become engaged in the same body of water, signalling becomes increasingly dangerous.
To manage these entangled nuclear dynamics, the Indian Ocean must be reconceptualised as one continuous maritime theatre in which individual crises could trigger a larger chain of escalation. Doing so requires re-centring the ocean in nuclear threat assessments. The current international system is based on a “continental gaze” that dictates maritime policy based on the ocean’s proximity to the nearest coastline or landmass. An ocean-centric perspective instead defines the maritime domain on its own terms. The ocean is not a space between landmasses, but rather a place where international trade, fishing, oil drilling, environmental conservation, research exploration, subsea cable infrastructure, port development, law enforcement, search and rescue, and naval engagements all layer on top of one another.
Recognising the Indian Ocean as a unified, contested, and nuclearised space is just the first step in preventing regional escalations. Policy makers around the world must develop crisis communication mechanisms that reflect the realities of strategic signals at sea. This could include new agreements to manage unplanned encounters between militaries, and new channels for early warnings about missile tests and bomber patrols among nuclear-capable states operating across the region. These mechanisms must be inclusive of both regional and external actors and tailored to the dynamics of maritime deterrence. Without them, the risk of escalation—triggered by a misunderstood patrol, an ambiguous bomber flight, or an unexpected missile test—will continue to grow.
SOURCE: thebulletin.org
