Introduction
Sea lines of communications (SLOCs) carry 80 percent of the world’s trade by volume, connecting global value chains, transporting raw materials and semi-processed goods to production hubs, and delivering finished products to consumers. SLOCs are therefore crucial for industrialization, economic growth, and job creation. Indo-Pacific SLOCs, whether carrying vital crude oil from the Middle East and Indian Ocean to Asian economic powerhouses or transporting finished products from these same countries to lucrative markets worldwide, constitute particularly critical arteries for Indo-Pacific economies. Disruption to SLOCs during armed conflict could therefore result in dire economic consequences.
As an illustration, the re-routing of SLOCs to avoid Houthi attacks in the Red Sea resulted in significant cost increases for shippers, which, in turn, raised the burden on consumers. A U.S. Defense Intelligence Agency assessment puts war-risk insurance for shippers following the Houthis’ attacks on SLOCs at roughly 1,000 percent higher than pre-war costs. Likewise, the recent Ukrainian drone strikes on Russian “shadow fleet” tankers led to a rise in Black Sea shipping insurance rates. Additionally, the outbreak of the war in early 2022 led to initial spikes in grain prices, as Ukraine’s Black Sea ports were deemed unsafe for commodity export.
Preparedness across the Indo-Pacific for such an eventuality is, at best, uneven. There is a need for regional countries to acquire the optimal naval assets, along with adequate munitions stockpiling, and to pair these national efforts with closer cooperation among like-minded partners to collectively ensure SLOC protection.
Safeguarding the Arteries in Peace
In peacetime, navies primarily perform deterrence and constabulary missions. The force requirements for such low-intensity missions are relatively modest. Surges of naval forces for political signaling—for example, China’s recent mobilization of at least 100 naval and coastguard vessels across regional waters—remain relatively rare, as scarce resources are required to cover a much wider maritime zone against mainly unconventional threats like smugglers and pirates. This is especially true for Southeast Asia, where available resource capacities are often disproportionately small compared to the vast maritime zones under national jurisdiction. The case of Indonesia serves as a representative example. While mustering sufficient forces to police these waters has been a perennial challenge for countries like Indonesia and the Philippines, the situation is perhaps more optimistic for the better-endowed Indo-Pacific powers, such as Australia, India, Japan, and South Korea. During peacetime, they have shared the burden of helping to preserve regional peace and stability when Washington has had to divert its attention elsewhere. For example, during the ongoing Middle East conflict, when U.S. naval forces had to be deployed to the theater, these U.S. allies helped fill the void. With the present Trump administration’s predilection for roping in U.S. allies and partners to share a greater security burden, such arrangements look set to become the norm rather than the exception.
Tussle for Access and Denial
If conflict breaks out in the Indo-Pacific, such as over Taiwan, there would be a scramble to safeguard key SLOCs. In such a scenario, a region-wide SLOC protection effort may be impossible, given that some countries could be belligerents. One may argue against such a contingency in which Beijing, in particular, would threaten those SLOCs, considering its own economic dependence on these vital arteries. However, it clearly depends on whether China envisages a short, sharp conflict or anticipates a prolonged campaign. In the former scenario, Beijing might seek to mitigate the cost of the impact on shipping. In the latter scenario, China’s stockpiling of vital commodities such as petroleum could enable a potentially drawn-out conflict while limiting economic fallout.
If China is a belligerent in an Indo-Pacific conflict, one could assume that a United Nations legal mandate for collective international actions to safeguard shipping would be impossible to attain, especially if Beijing, possibly with Moscow’s support, utilizes its veto power as a permanent member of the UN Security Council to block any resolution to that effect.
In the event of any Indo-Pacific conflict, the belligerents would seek to deny adversaries secure SLOC access while guaranteeing their own. A set of parallel efforts would be the most realistic scenario: a U.S.-led theater campaign involving close allies and perhaps partners, alongside unilateral national measures and “coalitions of the willing” outside the U.S.-led effort. U.S.-led efforts are also far from assured, as demonstrated by the initial Western responses to the Houthi threat. Divergences over Washington’s support for Israel over the Gaza conflict led to muted European participation in the U.S.-led Operation Prosperity Guardian, with Europeans establishing their parallel effort through the European Union Naval Forces Aspides. An Indo-Pacific war could potentially become divisive between Washington and its allies. Regardless, Washington’s SLOC protection efforts in such a contingency would likely at least be joined by close allies such as Australia, Japan, and South Korea.
Other regional countries would mainly undertake SLOC protection efforts within their jurisdictional waters. Yet effectively securing international waterways, such as the Straits of Malacca and Singapore, may prove challenging. In times of peace, the strait littorals—Indonesia, Malaysia, Singapore, and Thailand—may agree they hold sole responsibility for ensuring the safety of navigation through this chokepoint, while external parties could offer aid short of direct action. In times of conflict, however, this understanding might not hold. These concerned Southeast Asian parties may not muster sufficient naval capacities to effectively secure the straits on their own, even if it means—especially for Indonesia and Malaysia—diverting resources away from other maritime areas of interest.
In the absence of a UN mandate for collective action, “coalitions of the willing” could be a plausible approach to compensate for national capacity shortfalls.
A Practical Challenge about the Right Capability
The practical challenge goes beyond political, operational, and doctrinal obstacles. Besides sophisticated threats posed by submarines, for example, low-cost strike weapons such as one-way attack drones, as well as a panoply of ballistic and cruise missiles, as exemplified by the Houthis, would pose a major problem for navies trying to defend a designated maritime zone. In the Red Sea case, U.S. and allied navies deployed warships designed and optimized for anti-air warfare (AAW) to deal with the Houthi threat. In an Indo-Pacific conflict scenario, warships with similar capabilities would be critical to any SLOC protection effort. So far, only the U.S. and regional allied navies of Australia, Japan, and South Korea possess AAW-optimized surface combatants with powerful sensor and weapons payloads to detect, track, and target incoming aerial and missile threats.
Most other Indo-Pacific navies, particularly those in Southeast Asia, are structured as general-purpose fleets that lack dedicated AAW-optimized platforms. Even in areas where geography favours land-based air defense systems to plug these gaps, capacity remains insufficient. As such, any effective effort to safeguard SLOCs would require Southeast Asian navies to work in coordinated or joint fashion. Such an effort would heap a disproportionate burden on the navies with significant AAW capabilities. Singapore, for example, fields six frigates each equipped with a 32-cell vertical launch system (VLS) for Aster missiles. Thailand fields three frigates, each with an eight-cell VLS for 32 Evolved Sea Sparrow Missiles in quad-packed loadouts. These are all relatively short-range, point-defense-type AAW capabilities compared to the longer-range, area-defense AAW capabilities mustered by the U.S. and allied Indo-Pacific navies, represented by the Standard Missile (primarily, the SM-2) system. Moreover, with about 32 missiles per vessel, these Southeast Asian assets pale in overall weapons capacity compared to the surface combatants fielded by U.S. and Indo-Pacific allied navies, which average around 90 VLS cells on each vessel. Overall, Southeast Asian navies, without the support of better-armed U.S. and other allied counterparts, would struggle considering their current arsenals.
In a best-case scenario in which regional countries could cobble together a motley coalition of the willing for SLOC protection, there is also the question of sustaining the mission mandate in the event of a protracted conflict. Combat persistence would rely on the capacities on board the deployed naval assets. U.S. and allied navies mainly deployed comparatively more expensive surface-to-air missiles to deal with cheap Houthi drones and missiles. The cost equation squarely disfavours defending navies—with an SM-2 missile that costs $4 million apiece to deal with a drone costing just around $10,000—while also considering an optimum “one shot, one kill” situation. The rate at which the U.S. Navy was burning through its Standard SM-2 and other missile inventory within just a few months of the campaign against the Houthis led it to seek around $150 million in supplemental funding to replenish its fast-depleting stocks.
Preparing for the Worst
The Red Sea debacle clearly showed the need for close interstate cooperation, as well as requisite naval capabilities and capacities to deal with the extant “low-cost” threat. If the Houthis already posed a headache to even the most capable navies, what could be said about a more sophisticated and better-endowed threat actor? The Red Sea and Ukraine examples demonstrate the need to move beyond business-as-usual in preparing for the worst-case scenario in SLOC protection.
The U.S. and Indo-Pacific allied navies are still updating their AAW capabilities, including the future introduction of shipborne laser weapon systems designed as low-cost solutions to the drone threat. Smaller navies, especially in Southeast Asia, are not staying static either. Notably, Indonesia is introducing a new class of surface combatant, the Balaputradewa-class frigate, each with a 64-cell VLS that would make it Southeast Asia’s most powerful AAW-capable warship; meanwhile, the pair of Brawijaya-class (formerly Italy’s Thaon di Revel-class) offshore patrol vessels in service could receive their AAW armament (each presently fitted for but not with 16-cell VLS) in the near future. That said, while it is encouraging that regional navies—even some in Southeast Asia—continue to invest in naval forces, the possession of discrete, individual naval platforms no longer suffices.
Besides acquiring suitable naval platforms, it is necessary for all like-minded Indo-Pacific stakeholders—not just the U.S. and allies but also other partners—to build sustainable inventories of munitions that could allow for potentially protracted SLOC protection mandates. These munitions should also be stored in strategically located shore bases that are hardened and appropriately defended against enemy attacks. In the same vein, regional navies need to focus on sustaining adequate infrastructure, including maintenance and repair facilities, to support such high-intensity naval campaigns. At the national level, navies should begin working with other armed services to leverage land-based defence capabilities to contribute to SLOC protection.
Moreover, it is important to enhance naval cooperation with regional and extra-regional partners to promote closer naval interoperability. U.S. and Indo-Pacific allied navies, wcith their area defense-optimized AAW capabilities, could complement the point defense-optimized AAW capabilities of smaller regional navies, especially those in Southeast Asia, to create a more robust, multilayered air defense umbrella for SLOC protection. While such engagements have been taking place for decades, they have largely been uneven in terms of scope and depth. Some navies have practised together for high-intensity naval operations during armed conflicts, but most have mainly trained together to deal only with non-state actors, such as pirates and armed robbers at sea, or transnational terror organizations. It is more essential than ever for Indo-Pacific countries to promote naval cooperation to fight high-intensity SLOC protection campaigns in order to prepare effectively for a future major regional conflict.
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Collin Koh is a Senior Fellow at the Institute of Defence & Strategic Studies, a constituent unit of the S. Rajaratnam School of International Studies, based in Nanyang Technological University, Singapore. He primarily researches maritime security and naval affairs, especially in Southeast Asia.
Image Credit: Cooperation Afloat Readiness and Training 2000 (CARAT) by USN, PDM 1.0, via Wikimedia Commons
