From High Seas to Highlands Framing U.S. Defense Strategy With Southeast Asia’s Geography
By Caitlin P. Irby
The 2022 U.S. National Security Strategy prioritized competing with China, and this focus seems likely to continue with the new administration.1 Southeast Asia’s growing economic relevance and proximity to China mean that the United States can secure significant gains on numerous goals by focusing on this region. The region’s geography dramatically impacts American interests, and strategy-makers must account for these factors. Specifically, the U.S. military must prepare for a range of military operations but lacks a long-term strategy for operating in and engaging with the region. To successfully advance American interests, the U.S. military must procure access to a multitude of bases across the region, procure capabilities that enable maneuver in the region’s varied physical geographies, and develop a system of situational awareness capabilities that are resilient in the face of regional challenges.
In support of developing this strategy, this article identifies what features make Southeast Asia relevant to the United States and what potential flashpoints for conflict exist and outlines the characteristics of a potential conflict. With this information, the article then proposes specific steps to ensure that the U.S. military maintains the capabilities to protect American interests against potential threats. Without a more concerted strategy, the United States in general and the Department of Defense specifically risk losing influence and capability in the most dynamic and rapidly advancing region of the world—which could change the balance of global power.
Why Does Southeast Asia Matter?
The 2022 National Security Strategy asserted that competition between and among major powers will shape the coming decade. The strategy also identified China as “the only competitor with both the intent to reshape the international order and . . . [the] power to do it.”2 Southeast Asia potentially serves as the most significant region for competition between the United States and China due to rising economic relevance, its geographic proximity to China, and the potential for U.S. influence. The United States will need increased involvement in the region to counter Chinese efforts. Also, the projected growth of Southeast Asia in terms of population and economics makes the region a particularly important battleground between the United States and China. As part of the competition, the United States must actively court allies and partners around the region to assist in combating Chinese influence.
Economics. Today, Chinese engagement with Southeast Asia includes being the largest economic trading partner for every country in the region and expanding Chinese economic influence through projects such as the Belt and Road Initiative. For the United States, the February 2022 Indo-Pacific Strategy stated that the “prosperity of everyday Americans is linked to the IndoPacific.”3 Estimates suggest that over half a million U.S. jobs depend on trade with the region. Additionally, the U.S. and Southeast Asian economies execute complementary functions. Particularly with electronic machinery, American companies have integrated supply chains with producers in Southeast Asia.4 U.S. and other Western companies currently seek to “decouple” or “derisk” their presence in China, and many have relocated or plan to relocate to Southeast Asia.5 Southeast Asian countries also produce the second and third highest amounts of tin and first and second highest amounts of nickel in the world, both critical minerals for technology development and advancement.6 Given projections that Southeast Asia will grow to the fourth largest economy in the world by 2030, these economic linkages seem likely to grow in the future.7
Similarly, American allies also rely economically on the region. Japan and South Korea rely heavily on natural resources (predominantly oil and natural gas) that must transit through Southeast Asia to power the advanced economies of Northeast Asia.8 Southeast Asia represents Australia’s largest trading partner and a major source of migration.9
Geopolitics. China attempts to assert diplomatic dominance in the region, leveraging military and economic strength in exchange for concessions in international forums. Militarily, China aggressively asserts claims in the South China Sea and harasses neighboring military and civilian vessels.10 These actions are counter to the U.S. Indo-Pacific Strategy that sought to establish conditions favorable to the United States and allies in the region.11 The United States maintains treaty alliances with Australia, Japan, the Philippines, South Korea, and Thailand and robust partnerships with India, Indonesia, Malaysia, Singapore, and Vietnam.12 Many U.S. allies and partners struggle with security challenges associated with Chinese expansion and influence in the region as well. Indonesia, Malaysia, the Philippines, and Vietnam have active maritime and terrestrial disputes with China.13
Considering ongoing, aggressive Chinese diplomatic, economic, and military expansion, achieving U.S. goals will require additional engagement and a larger footprint in Southeast Asia. Competing with China means focusing on American interests and the interests of partners and allies we hope will compete with us, which requires focus and investment in Southeast Asia.
Competition and Conflict in Southeast Asian Geography
Southeast Asia consists of 11 countries including the landmass of the IndoChinese Peninsula as well as the island nations of Brunei, East Timor, Indonesia, Malaysia, the Philippines, and Singapore. To develop an effective strategy, the United States must consider the unique geographic factors that affect the region and drive the geopolitics of the countries within it.
Human Diversity. No field of human geography remains shared across the entire Southeast Asian region. Ethnicities, languages, varying economic development, and remaining demographic attributes all vary across the region and do not align nicely with(in) political borders. While the region largely avoided interstate war for over 30 years, most states recently experienced some form of domestic interethnic or religious strife including Islamic insurgencies in the southern Philippines and southern Thailand, anti-Chinese riots in Indonesia in 1998, and accusations of ethnic cleansing in Myanmar.14
In addition to this ethno-religious diversity, the economic and demographic profiles of the countries vary significantly. While Singapore maintains an advanced, service-based economy with an average income of over $67,000 per year, Cambodia relies on low-skill manufacturing such as garments, with an average income of approximately $1,700 per year.15 Thailand hosts the oldest population, with a median age of nearly 40, while Indonesia’s largest regional population has a median age around 30.16
These variations in human geography both within and across Southeast Asia inhibit these countries’ abilities to come to consensus both internally and within the Association of Southeast Asian Nations (ASEAN). This lack of consensus contributes to ASEAN’s design as more of a regional discussion forum than an intergovernmental organization capable of strong action. This poses a challenge for U.S. ambitions to place ASEAN as the central organizing body within the region. The factions within countries force the United States and allies to consider not only national politics but also subnational realities when addressing basing, locations of exercises, investments, and other engagements.
Monsoons. In the realm of physical geography, Southeast Asia experiences two monsoon seasons. The Northeast monsoon season runs from November through March, and the Southwest monsoon season runs from May through September, and they usually bring the largest annual rainfall amounts. Estimates indicate that climate change will cause shifts in the timing of the monsoons as well as a decrease in overall rainfall but an increase in rainfall intensity, resulting in more frequent incidents of damaging flooding. While large oceangoing ships remain largely unaffected by the monsoons and their transitions, higher intensity typhoons, flooding, and mudslides impact the viability of port infrastructure, air traffic, and logistics support.17 Additionally, weather systems complicate intelligence and surveillance operations regardless of the collection platform. This challenges all countries’ abilities to engage in combat operations.18
Archipelagos. The Malay Archipelago, including all or some of the countries of Brunei, Indonesia, Malaysia, the Philippines, and Singapore, dominates the geography of maritime Southeast Asia. The waters both separate and connect people across the islands, which serve as lily pads across the waters while also potentially constricting maritime transit.19 The contingent nature of the maritime and land domains makes operating in the region particularly challenging. China demonstrates this dual nature by building more islands in the South China Sea to extend its military reach but would struggle to sustain a presence on those islands under combat conditions.
Archipelagos particularly pose a challenge to the military principles of mass and security. Security within an archipelago is best achieved by dispersing forces across many islands and waterways and denying the adversary the opportunity to achieve a decisive operation. Offensive operations require mass to defeat entrenched defensive positions.20 As such, any military must maintain the ability to disperse across the region to achieve security and mass for the conduct of offensive operations.
The South China Sea. The South China Sea sits in the middle of Southeast Asia and competing political claims to resources within the sea make it the most likely point of conflict. Any competition or conflict in Southeast Asia between major powers will involve attempts to control the South China Sea. As a marginal sea bounded by islands, entrance and exit are restricted by straits near the islands of Banka, Karimata, Luzon, Malacca, Palawan, and Taiwan. Many of these straits have multiple countries bordering them. This means that any country bordering a particular strait could contest control of the straits. Consequently, multilateral engagement with all relevant countries would be required to secure transit. Additionally, the sea is largely shallow (over 50 percent of the sea has depths of less than 650 feet), and spotted with reefs, atolls, and small islands. Particularly for submarines, shallow waters impact their effectiveness and their procedures.21
Regional Flash Points
The U.S. military’s primary contribution to any Southeast Asian strategy should involve deterring armed conflict with China and winning any conflict that might arise despite deterrence efforts. As such, the military must remain apprised of potential sources of conflict while developing a strategy for the region. Of note, the United States should consider competing claims within the South China Sea and the international maritime chokepoint of the Strait of Malacca. Should conflict break out elsewhere in the Pacific (for instance, Taiwan), the United States and others would likely attempt to impose costs on China with a blockade of the Strait of Malacca.22
South China Sea Claims. With claims by six different countries and Taiwan, the South China Sea remains a highly contested area. At least eight territorial or maritime disputes exist in the region—many among Southeast Asian nations but many also involving Chinese claims. China’s “Nine Dash Line” competes with claims by Brunei, Indonesia, Malaysia the Philippines, and Vietnam. In 2016, the United Nations Convention on the Law of the Sea Permanent Court of Arbitration ruled against China’s claims in Philippines v. China, but China rejected the authority of the ruling.23 Tensions increased when China began reclaiming land on coral reefs and atolls and subsequently building military bases on them.24 Throughout 2023 and 2024, Chinese and Philippine maritime vessels clashed with water cannons, warning shots, and attempted rammings over contested claims at the Second Thomas Shoal. As a treaty ally with the Philippines, the United States became involved by flying intelligence aircraft while the Philippine Coast Guard conducted a resupply of their outpost on the Second Thomas Shoal.25 Incidents like these have high potential for miscalculation and escalation, but conflicts between Southeast Asian countries also occur. In 1998, the Vietnamese military fired on a Philippine fishing vessel in the vicinity of a contested reef.26 This combination of competing territorial claims and growing military presence makes the South China Sea the most likely spark to any regional crisis.
The Malacca Dilemma. China has long commented on its vulnerability to disruption of critical imports through the Strait of Malacca. Both historically and today, China relies on this trade route for imports of oil and natural gas from the Middle East.27 Even as China attempts to transition to more carbon-friendly technologies, Africa provides many of the raw materials and thus would utilize the same shipping routes. While China attempted to mitigate this vulnerability with an oil and natural gas pipeline from Myanmar to China and the funding of the Kra Canal in Thailand in 2018 to bypass the Strait of Malacca, the pipeline does not provide sufficient capacity to replace shipborne traffic, and the Thai government canceled the Kra Canal project in 2020.28
China lacks the ability to defend the Strait of Malacca, which would remain a critical supply line in any enduring conflict. As such, any armed conflict involving China, the United States, or other countries would likely attempt to restrict Chinese shipping through the strait.29 Consequently, conflict in a place such as Taiwan or the Senkaku Islands may still bring armed conflict to Southeast Asia.
How to Operate in Southeast Asia
Given the rising importance of Southeast Asia globally and the growing diplomatic, economic, and military competition for influence by other powers, the United States must adopt a strategy to conduct the full range of military operations. The geography of the region will influence the viability of any strategy. As such, the United States needs to address the requirement for resilient capabilities, including basing, maneuvering effectively across the region, and becoming more situationally aware of capabilities suited to the environment.
The military principles of mass and security frequently require trade-offs with each other. The massing of capabilities increases the likelihood of victory in battle, but the defeat of a large force leaves an entire military campaign vulnerable to counterattack. Acknowledging this dilemma, the U.S. Air Force developed the Agile Combat Employment concept that seeks to disperse operations to smaller locations that are “defensible, sustainable, and relocatable” while simultaneously maintaining the ability to mass combat effects against the adversary.30
Building Resilient Capabilities. For operations in Southeast Asia, building resilient capabilities requires large numbers of smaller bases close to potential conflict areas. The United States began executing this strategy in 2023, when it secured access to new basing in the Philippines. Despite this success, the Philippines represents one of the easiest locations in Southeast Asia because of the mutual defense treaty between the countries.31 In securing additional required access across the rest of the region, the United States will need to consider other factors.
The diversity across the region and consensus-style decisions associated with ASEAN mean that the United States must deal with each country unilaterally for basing negotiations. The varying political systems across the region mean that some countries (for example, Cambodia) may be completely unwilling to cooperate with the United States, while others (Indonesia) may be willing to grant access, but only under certain conditions.32 Monsoon seasons make some locations unsuitable or unreliable for operations (particularly airborne) during certain times of the year.33 Chinese military capabilities in the South China Sea pose risks that might make some bases nonviable during early stages of conflict.34 Because of these factors, the United States must develop a large and dispersed network of bases across a wide range of countries to maintain capability under a variety of circumstances.
Fortunately, the United States does not require permanent basing, a more complicated and sensitive request, but does require rotational access and access during crises. At a minimum, the United States will need access in the Philippines, Indonesia, and Indochina (most likely Singapore and Thailand) to maintain the dispersal across the region to achieve secure and redundant capabilities.
The United States successfully secured access to the Philippines with recent negotiations, but Indonesia will likely prove trickier. Indonesia seeks to avoid picking sides in a conflict between China and the United States due to deep economic and political ties to China and deep economic and military ties to the United States. Militarily, the United States and Indonesia agreed in May of 2024 to enhance training of Indonesia’s maritime security capabilities in light of aggressive Chinese maneuvers in the South China Sea.35 While Indonesia maintains strong military ties with the United States, it routinely feels neglected diplomatically.36 Additionally, the United States faces new challenges in its bilateral relationship due to its support for Israel in the war against Hamas, which puts the United States at odds with Muslim-majority Indonesia.37 Indonesia also maintains robust economic, military, and economic ties with Australia and India.38 If the “Quad” of Australia, India, Japan, and the United States approached Indonesia with offers of cooperation and potentially even an invitation to create a “Quint,” it would prove more powerful than a U.S. bilateral offer. It would also create more venues for U.S. engagement with Indonesia, alleviating some of Jakarta’s grievances over lack of diplomatic engagement. Additionally, deepening relationships between these countries economically (which is not currently within the scope of the Quad) would provide a more viable counter to China’s economic influence across the region.
On the Indochinese Peninsula the most likely partners consist of Singapore and Thailand. Both countries maintain strong military ties with the United States, which has a mutual defense treaty with Thailand and significant basing agreements and military sales with Singapore.39 Like Indonesia, these countries prefer to avoid picking sides between China and the United States largely due to economic considerations.40 In spite of this fact, the United States should continue to conduct more complicated and larger numbers of military exercises such as Cobra Gold in Thailand and Pacific Griffin in Singapore and capitalize on any diplomatic missteps by China to secure agreements contingent on Chinese aggression.41 As an example, the United States should continue to highlight Chinese aggression against the Philippines in the South China Sea, propaganda efforts in Southeast Asia, and declines in the Chinese economy. These efforts increase the likelihood that countries will assist the United States in countering China in the event of a military crisis in the region and increase the resilience of U.S. military presence.
Maneuver. Due to the geography of Southeast Asia, military maneuver becomes particularly challenging but no less necessary for success. Especially with forces dispersed for security, maneuver becomes a requirement for logistics and sustainment as well as for offensive advantage and to generate mass.42 In this context, the Department of Defense requires assets capable of moving personnel, equipment, and combat power quickly and securely to land and maritime basing in a wide range of circumstances, including unfavorable weather and contested by adversaries. While the Navy has invested significantly in the Littoral Combat Ship for this exact purpose, it needs to address the ongoing maintenance issues and criticism of the weapons capabilities to successfully address requirements for high-intensity conflict.43 Australia also debates how to field applicable capabilities to the archipelagic region with the added consideration of integration with foreign partners such as the United States and Japan.44
In addition to the ability to base and sustain in the region, the United States must develop and maintain the ability to maneuver in the South China Sea. While many acknowledge that the United States maintains a significant technological advantage in submarine warfare, many of these advantages become muted in the shallow waters of the South China Sea.45 The development of systems that could effectively operate in shallow waters, under threat from Chinese capabilities in the South China Sea, remains a significant gap. Uncrewed systems maintain significant advantages in this environment but face numerous technical challenges to implementation. Interconnected buoys and small uncrewed vessels could provide the communications network backbone for uncrewed vessels but must survive the challenging ocean conditions of the South China Sea in addition to potential adversary attacks. While not unique to the South China Sea, increasing range, battery life, and interoperability with other systems remain requirements to achieve the full potential of uncrewed vehicles.46
Situational Awareness. A final decisive military capability for the region rests with intelligence. One’s ability to detect an adversary’s location and capabilities and array them against one’s own remains the difference between victory and defeat. Southeast Asia poses numerous challenges to the ability to consistently detect an adversary. Detection of naval ships in open waters remains nearly as challenging as it was in World War II.47 Both land- and space-based sensors would struggle with the challenging atmospheric conditions associated with the tropics. The dense tropical vegetation of rural portions of the region and densely populated urban areas complicate detection capabilities.48
All these challenges come in addition to a broadly increasing technological capability to disrupt technical intelligence collection. The United States must develop sensors and platforms that overcome the environmental challenges of Southeast Asia in addition to any jamming and interference from an adversary. These capabilities must maintain connectivity across the dispersed operating locations and have sufficient mobility to keep up with maneuvering forces. While many of these capabilities exist, the U.S. Government and military currently struggle to build and implement a strategy for acquisition and fielding.
On the policy front, the United States needs to improve intelligence-sharing with key allies and partners in Southeast Asia for maximum situational awareness. Allies and partners could contribute to sensor emplacement and communications. The United States could also benefit from the on-the-ground knowledge and expertise provided by regional partners. These partners would participate only if they also gained from the intelligence collected. Concerns over security of the information and the potential for China to gain access to this information through regional partners, while valid, should be mitigated without preventing sharing of useful intelligence.
Conclusion
Historically, major world powers, including the United States, considered Southeast Asia a dispersed, disunified, and largely disempowered region of the world, including President Lyndon Johnson’s description of Vietnam as a “damn little piss-ant country.”49 Today, however, the Southeast Asian combined economy constitutes the fifth largest in the world, and economists project growth in the region will drive the global economy for years to come.50 Given U.S. goals to compete with China, Southeast Asia is now central to American foreign policy.
The human and physical geographic features of the region make conflict different from other regions. Characterized by diverse peoples, levels of economic development, and political systems, the region struggles to act as a unified block, making it vulnerable to exploitation by larger powers. Climatically, the monsoon seasons affect preparation for and execution of conflict in the region. The unique blend of land and sea, consisting of a large peninsula and the Malay Archipelago, makes the region unlike any other, with both land and sea acting as simultaneously connecting and dividing forces. Finally, at the physical center of the region lies the South China Sea. This sea, with its mostly shallow waters surrounding a deep-water basin and restricted access points, remains the most likely point of conflict in the region.
For the United States to achieve its foreign policy goals in Southeast Asia, the military must be capable of conducting a wide range of operations. To posture for these potential operations, the United States must secure access to a multitude of bases across the region, procure capabilities that enable maneuver in the region’s varied physical geographies, and develop a system of situational awareness capabilities that are resilient in the face of regional challenges. Accomplishing these goals will enable the U.S. military to conduct and succeed in operations ranging from humanitarian assistance to high-intensity conflict. Failure to set the stage for military actions will result in loss of influence and opportunities to pursue national interests in the region.
Notes
1 National Security Strategy (Washington, DC: The White House, October 2022), https://bidenwhitehouse.archives.gov/wp-content/uploads/2022/10/BidenHarris-Administrations-National-SecurityStrategy-10.2022.pdf.
2 National Security Strategy, 23.
3 Indo-Pacific Strategy of the United States (Washington, DC: The White House, February 2022), 3, https://bidenwhitehouse.archives.gov/wp-content/uploads/2022/02/U.S.-Indo-Pacific-Strategy.pdf.
4 Brian Harding and Kim Mai Tran, U.S.–Southeast Asia Trade Relations in an Age of Disruption (Washington, DC: Center for Strategic and International Studies, June 2019), https://www.csis.org/analysis/us-southeastasia-trade-relations-age-disruption.
5 “What Does ‘De-Risking’ Trade With China Mean?” The Economist, May 31, 2023, https://www.economist.com/the-economistexplains/2023/05/31/what-does-de-riskingtrade-with-china-mean.
6 Global Resources and Reserves (St. Albans, Hertfordshire, UK: International Tin Association, 2020), https://www. internationaltin.org/wp-content/ uploads/2020/02/Global-Resources-Reserves2020-Update.pdf; Sharon E. Burke et al., Critical Minerals: Global Supply Chains and Indo-Pacific Geopolitics, NBR Special Report #102 (Washington, DC: National Bureau of Asia Research, December 2022), https://www.nbr. org/wp-content/uploads/pdfs/publications/ sr102_criticalminerals_dec2022.pdf.
7 ASEAN Matters for America/America Matters for ASEAN, 6th ed. (Washington, DC: U.S.-ASEAN Business Council, 2023), https://www.usasean.org/sites/default/ files/2023-10/2023-ASEAN-Matters-forAmerica.pdf.
8 Nathalie Fau, “The Strait of Malacca’s ‘Littoral Transit States’: The Potential for a Cross-Border Energy Hub,” Hérodote 176, no. 1 (January 2020), 77–95, https://www.cairnint.info/journal-herodote-2020-1-page-77.htm.
9 Nicholas Moore, Invested: Australia’s Southeast Asia Economic Strategy to 2040 (Barton, ACT: Department of Foreign Affairs and Trade, September 2023), https://www. dfat.gov.au/sites/default/files/investedsoutheast-asia-economic-strategy-2040.pdf.
10 David Shambaugh, Where Great Powers Meet: America and China in Southeast Asia (New York: Oxford University Press, 2020).
11 Indo-Pacific Strategy of the United States, 5.
12 Indo-Pacific Strategy of the United States.
13 “What Is the South China Sea Dispute?” BBC, July 7, 2023, https://www.bbc.com/ news/world-asia-pacific-13748349.
14 Mohd Amin Amir and Zulafqar Ahmed, “Ethnic Conflicts in South Asia: Impediments to Regional Integration,” World Affairs: The Journal of International Issues 24, no. 3 (July– September 2020), 10–19, https://www.jstor. org/stable/48590640.
15 “Country Comparison: Singapore and Cambodia,” World Data, n.d., https:// www.worlddata.info/country-comparison. php?country1=KHM&country2=SGP.
16 “Country Comparison: Indonesia and Thailand,” World Data, n.d., https:// www.worlddata.info/country-comparison. php?country1=IDN&country2=THA.
17 Yen Yi Loo et al., “Effect of Climate Change on Seasonal Monsoon in Asia and Its Impact on the Variability of Monsoon Rainfall in Southeast Asia,” Geoscience Frontiers 6, no. 6 November 2015), 817–23, https://doi. org/10.1016/j.gsf.2014.02.009.
18 Norman Freedman, “American Sea Power Project: Geography Plays an OceanSized Role,” U.S. Naval Institute Proceedings 148, no. 6 (June 2022), https://www.usni. org/magazines/proceedings/2022/june/ american-sea-power-project-geography-playsocean-sized-role.
19 Bob Moyse, “Shaping a Concept of Archipelagic Warfare for the Australian Defence Force,” Defense.info, May 25, 2022, https:// defense.info/re-thinking-strategy/2022/05/ shaping-a-concept-of-archipelagic-warfare-forthe-australian-defence-force/.
20 Freedman, “American Sea Power Project.”
21 Lawson W. Brigham, “The South China Sea: Complex and Changing,” U.S. Naval Institute Proceedings 149, no. 1 (January 2023), https://www.usni.org/magazines/proceedings/2023/january/south-china-seacomplex-and-changing.
22 “The Malacca Dilemma: A Hindrance to Chinese Ambitions in the 21st Century,” Berkley Political Review, August 26, 2019, https:// bpr.berkeley.edu/2019/08/26/the-malaccadilemma-a-hindrance-to-chinese-ambitions-inthe-21st-century/.
23 “What Is the South China Sea Dispute?”
24 “China Has Fully Militarized Three Islands in South China Sea, U.S. Admiral Says,” Guardian, March 20, 2022, https:// www.theguardian.com/world/2022/mar/21/ china-has-fully-militarized-three-islands-insouth-china-sea-us-admiral-says.
25 Brad Lendon, “China-Philippines Maritime Standoff Escalating on Path That Could Drag U.S. Into Conflict, Analysts Warn,” CNN, December 13, 2023, https:// www.cnn.com/2023/12/13/asia/chinaphilippines-maritime-standoff-analysis-intl-hnkml/index.html.
26 Felipe Villamor, “Philippines Promises Vietnam a Full Investigation Into Fishermen’s Deaths,” New York Times, September 25, 2017.
27 Harsh Suri, “Explained—the Strait of Fear—Malacca,” The Geostrata, May 27, 2021, updated October 31, 2022, https://www. thegeostrata.com/post/explained-the-strait-offear-malacca.
28 Neslihan Topcu, “A Relationship on a Pipeline: China and Myanmar,” China Currents 19, no. 3 (2020), https://www. chinacenter.net/2020/china-currents/19- 3/a-relationship-on-a-pipeline-china-andmyanmar/; Paulo Aguiar, “Kra Canal: The Impossible Dream of Southeast Asia Shipping,” Geopolitical Monitor, April 16, 2025, https:// www.geopoliticalmonitor.com/kra-canal-theimpossible-dream-of-southeast-asia-shipping/.
29 Suri, “Explained.”
30 Air Force Doctrine Note 1-21, Agile Combat Employment (Washington, DC: Headquarters Department of the Air Force, August 23, 2022), https://www.doctrine. af.mil/Portals/61/documents/AFDN_1-21/ AFDN%201-21%20ACE.pdf. See also Ian D. Richardson, “Protecting ACE: Air Defense and Agile Combat Employment,” Joint Force Quarterly 117 (2nd Quarter 2025), 51–57, https://digitalcommons.ndu.edu/joint-forcequarterly/vol117/iss2/8/.
31 “Philippines, U.S. Announce Locations of Four New EDCA Sites,” Department of Defense, April 3, 2023, https://www. defense.gov/News/Releases/Release/ Article/3349257/philippines-us-announcelocations-of-four-new-edca-sites/.
32 Shambaugh, Where Great Powers Meet.
33 Impact of Geography on Air Operations in SEA, Project Contemporary Historical Examination of Current Operations (CHECO) Southeast Asia Report (Hickam Air Force Base, HI: Pacific Air Forces, Directorate of Tactical Evaluation, CHECO Division, June 11, 1970), https://apps.dtic.mil/sti/pdfs/ADA486707.pdf.
34 Brett Wessley, “Outflank China in the South China Sea,” U.S. Naval Institute Proceedings 143, no. 6 (June 2017), https:// www.usni.org/magazines/proceedings/2017/ june/outflank-china-south-china-sea.
35 Gusty Da Costa, “Indonesian, U.S. Military Leaders Deepen Security Cooperation,” Indo-Pacific Defense Forum, May 24, 2024, https://ipdefenseforum. com/2024/05/indonesian-u-s-militaryleaders-deepen-security-cooperation/.
36 Bich Tran, “A Renewed Focus on Indonesia-U.S. Relations,” Center for Strategic and International Studies, February 17, 2022, https://www.csis.org/analysis/renewed-focusindonesia-us-relations.
37 Sharon Seah et al., The State of Southeast Asia 2024 Survey Report (Singapore: ASEAN Studies Centre, April 2024), https://www. iseas.edu.sg/wp-content/uploads/2024/03/ The-State-of-SEA-2024.pdf.
38 Don McLain Gill, “How Closer IndiaIndonesia Security Ties Can Promote a Stable Indo-Pacific,” The Diplomat, December 22, 2021, https://thediplomat.com/2021/12/ how-closer-india-indonesia-security-ties-canpromote-a-stable-indo-pacific/; Yokie Rahmad Isjchwansyah, “What Can Indonesia Expect From Its Anticipated Defense Cooperation Agreement With Australia?” The Diplomat, April 11, 2024, https://thediplomat. com/2024/04/what-can-indonesia-expectfrom-its-anticipated-defense-cooperationagreement-with-australia/.
39 “U.S. Security Cooperation With Singapore,” Fact Sheet, Bureau of Political Military Affairs, Department of State, January 20, 2025, https://www.state.gov/u-s-securitycooperation-with-singapore/.
40 Seah et al., The State of Southeast Asia 2024 Survey Report.
41 “U.S. Security Cooperation With Thailand,” Fact Sheet, Bureau of Political Military Affairs, Department of State, January 20, 2025, https://www.state.gov/u-s-securitycooperation-with-thailand/; “U.S. Security Cooperation With Singapore.”
42 Moyse, “Shaping a Concept of Archipelagic Warfare for the Australian Defence Force.”
43 Brad Lendon, “In the Turbulent South China Sea, the U.S. Navy Bets on a Troubled Warship,” CNN, August 26, 2021, https:// www.cnn.com/2021/08/25/asia/us-navylittoral-combat-ships-pacific-south-china-seaintl-hnk-ml-dst/index.html.
44 Moyse, “Shaping a Concept of Archipelagic Warfare for the Australian Defence Force.”
45 Wessley, “Outflank China in the South China Sea.”
46 Inyeong Bae and Jungpyo Hong, “Survey on the Developments of Unmanned Marine Vehicles: Intelligence and Cooperation,” Sensors 23, no. 10 (May 2023), 4643, https://doi. org/10.3390/s23104643.
47/sup> Wessley, “Outflank China in the South China Sea.”
48/sup> Oleg Dubovik et al., “Grand Challenges in Satellite Remote Sensing,” Frontiers in Remote Sensing 2 (February 2021), https:// www.frontiersin.org/articles/10.3389/ frsen.2021.619818/full.
49/sup> David Halberstam, The Best and the Brightest (New York: Random House, 1972), 564.
50 ASEAN Matters for America/America Matters for ASEAN.