Center for American Progress

Southeast Asia: The Next Frontier of the U.S.-South Korea Alliance

Southeast Asia: The Next Frontier of the U.S.-South Korea Alliance

As the United States and South Korea expand their bilateral cooperation beyond Northeast Asia, here are some ideas on how they can chart a path forward in Southeast Asia.

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A soldier gestures from his position securing a road lined with the flags of member countries of the Association of Southeast Asian Nations (ASEAN), as well as regional dialogue partner countries.
A soldier gestures from his position securing a road lined with the flags of member countries of the Association of Southeast Asian Nations (ASEAN), as well as regional dialogue partner countries, at the conference venue in Phuket, Thailand, on July 21, 2009.

At their May 2021 summit meeting, U.S. President Joe Biden and South Korean President Moon Jae-in committed to bolstering cooperation with member states of the Association of Southeast Asian Nations (ASEAN) in order to create a “safe, prosperous, and dynamic region.”1 This declaration builds on recent efforts to expand the scope of the U.S.-South Korea alliance beyond security on the Korean Peninsula and toward the provision of public goods in Asia more broadly. While there are considerable opportunities for deeper coordination between the United States and South Korea—officially the Republic of Korea (ROK)—in the region, cooperation in Southeast Asia will not be without challenges. This issue brief examines current unilateral and bilateral cooperative initiatives in Southeast Asia as well as issues for policymakers to consider as they develop programs in the region.

To deepen their work in Southeast Asia, the United States and South Korea should be open to coordinating unilateral initiatives, not just creating bilateral programs and projects. They should also build more dialogue mechanisms that bring together U.S., South Korean, and ASEAN policy influencers to build relationships and identify opportunities for engagement. Importantly, that engagement should include discussion of youth leadership networking, infrastructure, and standards. Finally, the United States must both refine its unilateral Southeast Asia strategy and work to strengthen democratic norms and processes at home to maintain credibility in the region.

Current unilateral and bilateral efforts in Southeast Asia

The United States

Washington’s approach to ASEAN as an institution and ASEAN member states falls under the purview of “the United States’ vision for a free and open Indo-Pacific.”2 As articulated by Vice President Kamala Harris, this is a vision “of peace and stability, freedom on the seas, unimpeded commerce, advancing human rights, a commitment to the international rules-based order, and the recognition that our common interests are not zero-sum.”3 While not explicitly anti-China, this amounts to a U.S. commitment to strategic competition with China for influence across the region.

To execute this vision, the Biden administration is trying to follow the golden rule for the region, which is showing up. High-level officials—including Vice President Harris, Secretary of Defense Lloyd Austin, Secretary of Commerce Gina Raimondo, and Secretary of State Antony Blinken—have all made visits to the region during the first year of the Biden administration, and President Biden attended this year’s East Asia Summit (EAS) and U.S.-ASEAN Summit virtually; in contrast, former U.S. President Donald Trump attended only the 2017 U.S.-ASEAN Summit and never attended the East Asia Summit.4 The Biden administration has announced plans to develop an “flexible and inclusive economic framework” to drive engagement with the region, recognizing the need for a deeper U.S. economic presence in light of U.S.-China strategic competition and the 2017 U.S. withdrawal from what was then called the Trans-Pacific Partnership.5 The Biden administration is also investing in existing mechanisms that drive U.S. relations with partners in the region. At the October 2021 U.S.-ASEAN Summit, President Biden announced up to $102 million in new U.S. funding to support initiatives related to health, climate, economic development, and human capital as part of the U.S.-ASEAN Strategic Partnership.6

However, the Biden administration’s attempts to court Southeast Asian partners and allies have left some in the region concerned. It took more than half a year for the Biden administration to kick off high-level visits to the region, and the initial highest-level visits took place in Singapore and Vietnam, rather than regional heavyweight Indonesia or longtime ally Thailand.7 Biden’s leader-level engagement did not begin in earnest until October 2021.8 Meanwhile, there are no nominations yet to fill the open ambassador posts at ASEAN or in allies Thailand and the Philippines.9 While the Biden administration’s efforts are an improvement over those of the Trump administration, analysts at the United States Studies Centre argue that U.S. efforts lack comprehensiveness and a well-defined economic component.10 These concerns are illustrative of the challenge of prioritization that inherently comes with the immense and influential portfolios that U.S. senior leaders must manage, as well as the constraints presented by the domestic politics of trade.

U.S. efforts in the region are often contrasted with those of China, as Southeast Asia is seen as a battleground for influence between the two powers. For example, on the economic front, the Regional Comprehensive Economic Partnership—whose signatories include China and all ASEAN member states, but not the United States—will go into effect in the new year.11 In terms of high-level engagement, Chinese Foreign Minister Wang Yi visited every ASEAN country over the course of 2020 and 2021.12 China’s attention to Southeast Asia demonstrates the challenges that U.S. leaders face when it comes to maintaining regional influence. In these competing attempts to court favor, some policy leaders in the region are concerned that Southeast Asian governments will be pressured by Washington and Beijing to choose sides. This is a choice Southeast Asian political elites have made clear they do not want to make: A mere 4 percent of surveyed elites across ASEAN think that it is in ASEAN’s best interests to pick sides.13 While Biden officials insist that the United States is not asking Southeast Asian countries to make a choice, it is difficult to insulate Washington’s approach to the region from great power competition.14

South Korea

The Moon administration has made improving South Korea’s ties with ASEAN member states a central tenet of its foreign policy. First announced in 2017, the New Southern Policy (NSP) promotes stronger ties with ASEAN member states and India to diversify South Korea’s foreign policy as it hedges against great power competition between the United States and China.15 The NSP marks the first South Korean diplomatic initiative focused on Southeast Asia.16 Seoul is seeking a hedge because when tensions rise between the United States—South Korea’s top security partner—and China, its top economic partner, South Korea can become caught in the crossfire. Seoul learned this lesson when the alliance deployed a Terminal High Altitude Area Defense (THAAD) battery to South Korea only for China to inflict billions of dollars in economic retaliation. By deepening ties, particularly economic links, with Southeast Asia, South Korea seeks to reduce its economic dependence on China.

South Korea’s NSP is built on three pillars: people, peace, and prosperity. And in 2020, the Moon administration updated the NSP to the “NSP Plus” with the addition of seven initiatives: 1) combating COVID-19 and improving public health; 2) supporting people-centered education to develop human resources and understanding of Korea; 3) gaining a deeper mutual understanding through culture; 4) building a mutually beneficial and sustainable economy; 5) enhancing quality of life through infrastructure development; 6) developing industries with innovative technology; and 7) shaping a community of greater safety and peace.17 As part of the NSP, the Korean Ministry of Foreign Affairs has also elevated relations with ASEAN member states from a division to its own bureau.18

Analysts of the NSP find that the initiative has been unbalanced in its focus on the “prosperity” pillar and uneven in its implementation. Hoang Thi Ha and Glenn Ong of the Institute of Southeast Asian Studies (ISEAS)-Yusof Ishak Institute note that “the NSP has been primarily driven by a strong economic imperative rather than a strategic thrust” and that economic engagement remains disproportionately directed toward Vietnam, a country with which South Korea already has deep economic ties.19 South Korea is Vietnam’s largest foreign investor, and in 2019, Vietnam was South Korea’s third-largest export market, while South Korea was the second-largest source of imports in Vietnam.20 Choe Wongi at the Center for ASEAN-India Studies at the Korea National Diplomatic Academy similarly finds that the NSP is limited by Seoul’s desire to avoid sensitive security issues.21 And Kathryn Botto, a former senior analyst at the Carnegie Endowment for International Peace, reaches a similar conclusion: The “prosperity” pillar has received the most attention, while the “peace” pillar remains underdeveloped. She also notes that the initiative lacks clear goals and a well-defined underlying strategy.22

Bilateral efforts

While the Moon administration has been hesitant to sign onto U.S. initiatives that leverage “free and open Indo-Pacific” branding, the two countries have been elevating cooperation in Southeast Asia in their bilateral relationship.23 In some cases, they have added the issue to the agenda of existing mechanisms such as the U.S.-Republic of Korea Information and Communication Technology Policy Forum and the U.S.-ROK Energy Security Dialogue.24 They have also created new dialogue mechanisms that bring together stakeholders across the U.S. and South Korean governments: The two governments held the inaugural U.S.-ROK Indo-Pacific Strategy-New Southern Policy Dialogue in August 2020 under the Trump administration, and the governments launched the ROK-U.S. Policy Dialogue on ASEAN and Southeast Asia in May 2021 with the advent of the Biden administration.25 At this second dialogue, the two sides discussed current efforts and opportunities for collaboration on a wide range of topics—from youth networking and maritime capacity building to ASEAN’s digital transition and greenhouse gas emissions. Finally, the countries are developing joint projects, such as implementing an action plan on the promotion of women’s economic empowerment, partnering with the Cambodian government to bolster public health, and building capacity on water data utilization in the Mekong region.26 Notably, these joint efforts avoid the traditional security realm and instead focus on issues related to development and human security.

Cooperation in Southeast Asia is an opportunity to leverage the relationships and capacity undergirding the U.S.-South Korea alliance while avoiding politically fraught issues such as countering malign Chinese behavior, improving Japan-South Korea relations, or engaging in diplomatic negotiations with North Korea. The two countries are also each uniquely qualified to deliver public goods to the region. South Korea has gone from recipient to donor of official development assistance (ODA), while the United States is the world’s largest provider of ODA. There is space for the two countries to share lessons learned—from the United States on how to strategize ODA provision and from South Korea on how to better interact with recipient countries. However, any attempt to cooperate, whether through ODA or other mechanisms, will require a deep understanding of both the demand for assistance as well as the supply.

Other considerations in addressing regional challenges

As the United States and South Korea chart paths for tackling regional challenges, they must carefully assess how to best serve the needs and desires of Southeast Asian nations. Southeast Asia is a large and diverse region: There is not a one-size-fits-all approach to the region’s institutions and member states. Any attempt to make progress on shared concerns such as climate change, public health, or infrastructure provision should not appear as the allies imposing their desire for cooperation on recipient countries or simply as a means of bolstering the U.S. position vis-à-vis China.

Meanwhile, U.S. policymakers must recognize that there are limits to what the United States and its partners can achieve in the region, particularly when it comes to supporting democracy or otherwise promoting liberal governance. The recent coups in Thailand and Myanmar, growing illiberalism in the Philippines, erosion of democratic norms in Indonesia, and the elimination of the opposition in Cambodia are indicative of a regional trend of democratic backsliding. Against this backdrop, Southeast Asian governments are unlikely to welcome U.S.-South Korea initiatives focused on promoting democratic institutions or civil liberties but will welcome infrastructure investment, support for their transition to cleaner sources of energy, and other programs to support their economic development. However, the United States and South Korea may also be able to adapt Japan’s principles for “quality infrastructure” investment, using infrastructure projects to promote good governance, incorporate environmental and social considerations, and provide opportunities for local businesses and workers.27 Without explicitly opposing China or trying to impose liberal values on reluctant partners, articulating a similar set of principles for U.S.-South Korea initiatives could nevertheless advance good governance and create more space for civil society. This could also tie into the U.S.-Japan-Australia “Blue Dot Network,” which seeks to certify infrastructure projects that meet certain standards.28

On the supply side, Washington and Seoul must decide what they want to—and are willing to—provide to the region. Through its implementation of the NSP, Seoul has demonstrated that it has limited interest in providing traditional security assistance that could be perceived as strengthening an anti-China bulwark. Washington, however, is treaty allies with two Southeast Asian nations and maintains important military access arrangements with Singapore. While there may be some space for coordination, for example, in promoting South Korean defense sales to Southeast Asian partners, the two nations are unlikely to have shared desires to engage in more comprehensive security cooperation with Southeast Asian governments.

Both partners must also consider whether resources devoted to cooperation in Southeast Asia are the best use of those resources. For instance, they must answer the questions: Is bilateral cooperation adding value, or would a given project be completed just as well unilaterally? Could a bilateral approach in fact harm the success of a project? Is cooperation unduly distracting alliance managers from core alliance concerns related to the security of the Korean Peninsula?

Cooperation for cooperation’s sake is not inherently a poor use of resources: Cooperative mechanisms build relationships, socialize ideas, and demonstrate the credibility of U.S. and South Korean commitments to Southeast Asia. However, the two partners must carefully consider whether cooperation in the greater region aids or hinders the achievement of their goals. For example, if South Korea were to sponsor legislative exchanges for partners in the region, it might be seen as less of a heavy-handed democracy promotion program than would a similar program run by the United States or a joint program.


Looking forward, the United States and South Korea should consider the following as they deepen their work in Southeast Asia:

  • Be open to coordination, not just cooperation: In some cases, coordinating unilateral work will do more good than creating joint U.S.-South Korea projects. Coordination will help deconflict projects and ideas while also building relationships among relevant stakeholders that can be leveraged for future bilateral work. In cases where the recipient country is more skeptical of cooperation with the United States, U.S. willingness to support unilateral South Korean projects rather than insisting on alliance branding could at times improve these initiatives’ efficacy.
  • Build mechanisms to foster U.S.-ROK-ASEAN dialogue and develop relationships among policy communities: The United States and South Korea should build mechanisms at the Track I (governmental) and Track II (nongovernmental) levels to improve coordination and collaboration with partners in ASEAN. Traditionally, U.S.-South Korea alliance experts have focused on bilateral affairs related to peninsular security and Northeast Asia. However, to improve the efficacy of cooperation and coordination in Southeast Asia, the two nations should develop mechanisms bringing together U.S.-South Korea alliance, Korea-Southeast Asia, and U.S.-Southeast Asia experts. This is, in part, happening through the ROK-U.S. Policy Dialogue on ASEAN and Southeast Asia and could be expanded into the nongovernmental space through private and public funding. Dialogue structures could include both multilateral dialogues with stakeholders from multiple ASEAN member states as well as trilateral dialogues with target countries such as Vietnam or Indonesia. In addition to building relationships, these mechanisms would foster targeted conversations on ideas for joint projects and policy coordination.
  • Leverage the Young Southeast Asian Leaders Initiative (YSEALI) to develop people-to-people ties: People-to-people connections are a pillar of the NSP, and YSEALI is the premier U.S. mechanism for youth engagement in Southeast Created in 2013 during the Obama administration, nearly 150,000 young people across ASEAN are members of the YSEALI network, and more than 5,000 people have participated in YSEALI programs.29 The two countries should think about ways to leverage YSEALI to invest in people-to-people ties: This could include U.S. support for South Korea as it develops its own youth leadership development program or co-sponsorship of youth exchange programs. The two countries are exploring opportunities to leverage YSEALI and should continue to pursue these efforts.30
  • Continue conversations on infrastructure and standards: The United States and South Korea signed a memorandum of understanding in 2019 to support infrastructure development through “market-oriented, private sector investment.”31 In addition to catalyzing private investment, the two governments can also discuss ways to coordinate public financing and ODA to support projects in the region that advance shared goals such as green transition and digitalization. Following discussions at the 2021 U.N. Climate Change Conference (COP26) on the role that green finance must play in promoting the transition to cleaner forms of energy in developing countries, the two governments should also discuss coordinating green finance standards for projects in Southeast Asia.
  • Invest in unilateral Southeast Asia strategy: For U.S. and U.S.-South Korea assistance to be most effective, it must be coupled with a comprehensive U.S. strategy toward the region that demonstrates credibility and desire to contribute positively to the region on the region’s terms. Basic steps in this direction include the further development of the Indo-Pacific economic framework and the nomination and confirmation of ambassadorial posts in the region.
  • Bolster democratic institutions at home: While there is not high demand for democracy promotion among ASEAN countries, if the United States wants to support democratic values in the region or not have rhetoric of “shared values” perceived as a code for competition with China, it must strengthen and protect its own democracy. Domestic attempts to undermine U.S. democracy are not only harmful in and of themselves but also undermine U.S. leadership abroad. As Republican officials block efforts to secure voting rights and pass laws politicizing the administration of elections after attempts to overthrow the results of the 2020 presidential race, U.S. democracy is fragile.32 Preaching about the importance of democracy abroad rings hollow in light of these illiberal realities at home.


Both the United States and South Korea are attempting to increase engagement with ASEAN, and as an alliance with deep relationships, technical know-how, and strong economies, the two nations are well-positioned to cooperate bilaterally and multilaterally in the region. However, the two countries are not necessarily aligned on what they hope to provide to the region: While the United States has articulated a vision for the region based on upholding values and the liberal, rules-based international order, the South Korean government has been more circumspect in how it engages with the region. Given these differences, the two countries will need to assess where their desire to provide what kinds of assistance overlap with the desires of regional partners. While South Korea is, in the near term, unlikely to support programs that seem tied to U.S. strategic objectives, there seems to be overlap in a desire to address nontraditional security threats and promote economic development. It is a net positive for both the region and the global community to support strong and resilient Southeast Asian countries, and the alliance should find synergies to maximize what they can provide to the region.

This issue brief is the third in a series of publications from the Center for American Progress addressing a progressive vision for the U.S.-South Korea alliance. It was written based on consultations and conversations with a network of progressive U.S. and South Korean foreign policy thinkers. The Center for American Progress thanks the Korea Foundation for its support of this project.


  1. The White House, “U.S.-ROK Leaders’ Joint Statement,” Press release, May 21, 2021, available at
  2. Ibid.
  3. The White House, “Remarks by Vice President Harris on the Indo-Pacific Region,” Press release, August 24, 2021, available at
  4. The White House, “Statement from Senior Advisor and Chief Spokesperson Symone Sanders on Vice President Kamala Harris’s Upcoming Visit to Singapore and Vietnam,” Press release, July 30, 2021, available at; U.S. Department of Defense, “Statement From Pentagon Press Secretary John F. Kirby on Upcoming Secretary of Defense Travel,” Press release, July 19, 2021, available at; U.S. Department of Commerce, “U.S. Secretary of Commerce Gina Raimondo Announces First Travel to Asia,” Press release, November 7, 2021, available at; U.S. State Department “Travel to the United Kingdom, Indonesia, Malaysia, Thailand, and Hawaii, December 9-17, 2021,” available at (last accessed December 2021); The White House, “Readout of President Biden’s Participation in the East Asia Summit,” Press release, October 27, 2021, available at; The White House, “Readout of President Biden’s Participation in the U.S.-ASEAN Summit,” Press release, October 26, 2021, available at; Reuters, “Biden to attend ASEAN summit Trump skipped after 2017,” CNBC, October 25, 2021, available at
  5. The White House, “Readout of President Biden’s Participation in the East Asia Summit”; Kentaro Iwamoto, “U.S. aims for ‘flexible and inclusive’ Indo-Pacific framework,” Nikkei Asia, November 18, 2021, available at
  6. The White House, “Fact Sheet: New Initiatives to Expand the U.S.-ASEAN Strategic Partnership,” Press release, October 26, 2021, available at
  7. See Seng Tan, “Biden’s underwhelming engagement with Southeast Asia,” East Asia Forum, October 2, 2021, available at; Charles Dunst, “Biden has not lived up his promises for Southeast Asia,” ThinkChina, July 2, 2021, available at
  8. See Seng Tan, “Biden’s underwhelming engagement with Southeast Asia.”
  9. American Foreign Service Association, “Tracker: Current U.S. Ambassadors,” available at (last accessed December 2021).
  10. Ashley Townshend and others, “Correcting the Course: How the Biden Administration Should Compete for Influence in the Indo-Pacific” (Sydney: United States Studies Centre, 2021), available at
  11. Yen Nee Lee, “World’s largest trade deal will come into force in January. The U.S. won’t be part of it,” CNBC, November 3, 2021, available at
  12. Lye Liang Fook, “Wang Yi’s Southeast Asia Tour: Significance and Challenges,” ISEAS Perspective, February 4, 2021, available at; Hoang Thi Ha and Le Hong Hiep, “Wang Yi’s Visit to Vietnam: Reasserting Influence, Regaining Balance,” ISEAS Perspective, September 22, 2021, available at
  13. Sharon Seah and others, “The State of Southeast Asia: 2021 Survey Report” (Singapore: ISEAS-Yusof Ishak Institute, 2021), p. 32, available at
  14. Yen Nee Lee, “Kamala Harris says Asia won’t have to choose between the U.S. and China,” CNBC, August 24, 2021, available at
  15. Darren Whiteside, “South Korea’s Moon unveils new focus on Southeast Asia,” Reuters, November 9, 2017, available at
  16. Yoon Ah Oh, “Korea’s New Southern Policy: Progress, Problems, And Prospects,” East-West Center 513 (2020), available at
  17. Presidential Committee on New Southern Policy, “New Southern Policy Plus,” available at (last accessed December 2021); Do Je-hae, “Moon announces ‘New Southern Policy Plus strategy’,” The Korea Times, November 11, 2020, available at
  18. Yonhap News Agency, “S. Korea’s foreign ministry to create ASEAN bureau,” February 20, 2019, available at
  19. Hoang Thi Ha and Glenn Ong, “Assessing the ROK’s New Southern Policy towards ASEAN,” ISEAS Perspective 7 (2020): 1–12, available at
  20. Hai Yen, “Vietnam remains favorite investment destination for South Korea amid Covid-19,” Hanoi Times, August 5, 2021, available at; World Integrated Trade Solution, “Korea,” available at (last accessed December 2021); World Integrated Trade Solution, “Vietnam,” available at (last accessed December 2021).
  21. Choe Wongi, “‘New Southern Policy’: Korea’s Newfound Ambition in Search of Strategic Autonomy” (Paris: French Institute of International Relations, 2021), available at
  22. Kathryn Botto, “South Korea Beyond Northeast Asia: How Seoul Is Deepening Ties With India and ASEAN” (Washington: Carnegie Endowment for International Peace, 2021), available at
  23. Andew Yeo, “South Korea and the Free and Open Indo-Pacific Strategy,” Center for Strategic and International Studies, July 20, 2020, available at
  24. U.S. State Department, “The United States of America and The Republic of Korea on Working Together to Promote Cooperation between the Indo-Pacific Strategy and the New Southern Policy,” Press release, January 20, 2021, available
  25. Ibid.; South Korea Ministry of Foreign Affairs, “ROK-U.S. Policy Dialogue on ASEAN and Southeast Asia,” Press release, May 13, 2021, available at
  26. Ibid.; Mekong-U.S. Partnership, “United States, South Korea, and Mekong River Commission Partnership Launches,” Press release, July 28, 2021, available at
  27. Kentaro Sonoura, “Japan’s initiatives for promoting ‘Quality Infrastructure Investment’” (Tokyo: Japan Ministry of Foreign Affairs, 2017), available at
  28. U.S. State Department, “Blue Dot Network,” available at (last accessed December 2021).
  29. U.S. State Department, “[FACT SHEET] Young Southeast Asian Leaders Initiative (YSEALI),” Press release, September 9, 2020, available at
  30. The White House, “FACT SHEET: United States – Republic of Korea Partnership,” Press release, May 21, 2021, available at
  31. U.S. Department of the Treasury, “United States and Republic of Korea Sign Framework to Strengthen Infrastructure Finance and Market Building Cooperation,” Press release, October 17, 2019, available at
  32. Juana Summers and Deirdre Walsh, “Democrats’ biggest push for voting rights fails with no Republicans on board,” NPR, October 20, 2021, available at; Matt Vasilogambros, “Republican Legislators Curb Authority of County, State Election Officials,” The Pew Charitable Trusts, July 28, 2021, available at; Karen Yourish, Larry Buchanan, and Denise Lu, “The 147 Republicans Who Voted to Overturn Election Results,” The New York Times, January 7, 2021, available at

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Tobias Harris

Former Senior Fellow

Abigail Bard

Former Policy Analyst, Asia

Haneul Lee

Former Research Assistant

Explore The Series

For nearly 70 years, the U.S.-South Korea alliance has been a linchpin of security in the Indo-Pacific. In recent years, the two governments have been working together to expand their scope of cooperation from beyond the peninsula to the broader region.

Over the course of 2021, experts at the Center for American Progress have led a project bringing together a network of self-identified progressives from the United States and South Korea to identify pain points, highlight convergences, and generate new ideas for the U.S.-South Korea alliance. Based on the results of the network’s conversation, CAP released three issue briefs discussing the role of the U.S.-South Korea alliance as it pertains to North Korea, China, and Southeast Asia. CAP thanks the Korea Foundation for its support of this project.


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