Click here to download or print the full text.

This essay is the second in a series that examines the South Korean nuclear debate from regional perspectives.

South Korea’s potential pursuit of nuclear armament marks a critical juncture in its relations within the Asia-Pacific, potentially straining ties with regional countries like Indonesia. As a strong advocate for non-proliferation and regional stability, Indonesia would likely view a nuclear-armed South Korea with concern. According to an April 2024 poll by Victor Cha at the Center for Strategic and International Studies (CSIS), 66% of South Korean elites opposed nuclear proliferation, primarily due to fears of reputational damage and international sanctions.^[1]

However, public support for South Korea acquiring nuclear weapons has increased, rising from 60.2% in 2023 to 66% in 2024, according to a survey by the Korea Institute for National Unification (KINU).^[2] South Korea’s nuclearization could undermine its bilateral relationship with Indonesia, intensifying regional tensions, and erode trust between the two nations.

While previous studies have comparatively examined public^[3] and elite^[4] perceptions across countries such as Indonesia, Australia, and Taiwan, this paper focuses solely on Indonesia’s perspective on a potential nuclear-armed South Korea. It explores Indonesia’s potential response, including diplomatic and multilateral actions, and the broader implications for Indonesia-South Korea bilateral relations and regional stability.

Indonesia’s non-proliferation record and views of a nuclear South Korea

Indonesia has long been a strong and consistent supporter of nuclear non-proliferation and disarmament. It signed and ratified the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) in the 1970s, the Comprehensive Nuclear-Test-Ban Treaty (CTBT) in 2011, and most recently ratified the Treaty on the Prohibition of Nuclear Weapons (TPNW) in September 2024. Beyond its participation in international non-proliferation and disarmament treaties, Indonesia has consistently demonstrated strong opposition to actions by other states that could threaten or undermine the global non-proliferation and disarmament regime.

This opposition includes its support for United Nations Security Council (UNSC) sanctions on Iran in 2007 (Resolution 1747), when Indonesia was a non-permanent member of the UNSC. Although Indonesia’s position later shifted due to domestic public and political pressures, leading to its abstention on further sanctions in Resolution 1803, it did not vote against them.

Indonesia is currently campaigning for a non-permanent seat on the UNSC for 2029-2030. If South Korea were to pursue a nuclear weapons program, Indonesia would likely support UNSC sanctions. While there might be some disagreement within bureaucratic elites – such as opposition from the Ministry of Trade and the Ministry of Industry, given South Korea’s status as an important trading partner – domestic resistance to sanctioning South Korea would likely be weaker than in the case of Iran, where religious and ideological factors, and political plays at the time, played a larger role.

As a result, Indonesia’s support for sanctions on South Korea would likely be stronger and less likely to be reneged. Even if Indonesia does not serve on the UNSC at the time of Seoul’s proliferation, it would follow and adhere to any sanctions imposed on South Korea. Therefore, it is crucial that the UNSC remain functional and unified despite any geopolitical developments that may arise.

Indonesia has also demonstrated strong opposition to North Korea’s nuclear weapons program. Whenever North Korea conducted a nuclear test, Indonesia consistently issued statements condemning Pyongyang’s actions, emphasising the risks of proliferation and instability in the region. Although Indonesia established diplomatic relations with North Korea long before it did with South Korea, North Korea’s nuclear weapons policy has tarnished its reputation and strained its relations with Indonesia.

Beyond its inward-looking nature and lack of economic development, North Korea’s ongoing nuclear tests and ballistic missile launches, which Indonesia has regarded as threats to regional security, have led to its perception in Indonesia as not being a respectable member of the international community. If South Korea were to pursue nuclear proliferation, Dewi Fortuna Anwar, Research Professor at the Research Centre for Politics at the National Research and Innovation Agency (PRP-BRIN), warns that “Indonesia will view Seoul in the same way it views Pyongyang – as a rogue state.”^[5]

Indonesia has also consistently been wary of developments that may undermine the global nuclear non-proliferation and disarmament regime or contribute to regional instability, even when those developments are not directly in pursuit of proliferation. A clear example is its response to AUKUS, where, in September 2021, Indonesia issued a five-point statement that stated how it “takes note cautiously of the Australian Government’s decision to acquire nuclear-powered submarines” and “stresses the importance of  Australia’s commitment to continue meeting all of its nuclear non-proliferation obligations.”^[6] Some scholars in the IR community have argued that Indonesia’s stance has softened since then, citing then-President Jokowi’s May 2023 statement that AUKUS (and the Quad) should be seen “as partners, and not competitors.”^[7]

The Indonesian Ministry of Foreign Affairs, however, has maintained a more cautious and consistent position. In March 2023, it reiterated that “Indonesia expects Australia to remain consistent in fulfilling its obligations under the NPT and IAEA Safeguards, as well as to develop with the IAEA a verification mechanism that is effective, transparent and non – discriminatory.”^[8]

If South Korea were to acquire nuclear-powered submarines, Indonesia would likely respond with concern and caution. Given South Korea’s advanced nuclear technology and capability to potentially develop such submarines indigenously, Jakarta might worry that this development could shift the regional balance of power and prompt an arms race. Considering the cooperative defence agreements between South Korea and Indonesia, including past submarine contracts, Indonesia might also assess how this new capability could impact future defence collaborations. Additionally, Indonesia may raise the issue within ASEAN, advocating for dialogue on security implications to reinforce the Southeast Asia Nuclear-Weapon-Free Zone and maintain regional stability.

Given Indonesia’s high level of caution toward Australia’s nuclear-powered submarines and their potential impact on the already fragile non-proliferation regime, it is likely that if South Korea were to pursue nuclear latency – or anything short of full proliferation – Indonesia would still express deep concern. Indonesia would likely oppose any nuclear pathway for South Korea, including indigenous development of nuclear weapons or nuclear-powered submarines. Such actions by South Korea would likely strain its relations with Indonesia.

Challenges ahead for Indonesia and a nuclear-armed South Korea

The Indonesia-South Korea relationship is currently stronger than ever. Having celebrated the 50th anniversary of formal diplomatic relations in 2023, President Yoon Suk Yeol is eager to use the landmark anniversary to enhance cooperation between Seoul and Jakarta.^[9] Indonesia and South Korea have built a partnership based on shared economics and strategic interests, as well as overlapping identities and values. Expanded bilateral relations have been established through a “special strategic partnership” framework since 2017. South Korea’s decision to pursue nuclear weapons would pose a significant threat and present unprecedented challenges to Indonesia-South Korea relations.

Both strategic and economic cooperation has grown significantly between Indonesia and South Korea, with economic cooperation taking precedence in the relationship. In terms of strategic cooperation, Seoul and Jakarta have forged strong ties through joint projects such as the KF-21 Boramae Fighter jet, submarine deals, and increasing military cooperation through joint training and educational exchanges.^[10] However, challenges like delayed payments and stalled contracts continue to persist.^[11]

On the economic front, although the Indonesia-Korea trade partnership has not yet reached the same USD value of goods and services exchanged as that with other regional great powers, progress has been encouraging. The Indonesia-Korea Comprehensive Economic Partnership Agreement (IK-CEPA), which came into force on 1 January 2023, has been a key instrument in eliminating tariffs and boosting trade and investment.^[12] South Korea has emerged as a key investor in Indonesia, particularly in green energy, infrastructure development, and electric vehicle production, with significant milestone projects currently underway. At COP29 Azerbaijan, the new Prabowo administration introduced a renewable energy development program, aiming to add 75 GW of capacity through solar, wind, hydropower, geothermal, and nuclear power plants.^[13] In line with this ambition, Indonesia and South Korea agreed to expand energy cooperation in November 2024, reaffirming an MOU signed in 2022 that included cooperation on small modular reactors (SMR).^[14]

In a hypothetical situation where South Korea officially takes steps to develop nuclear weapons, it could expect to be sanctioned by the UNSC for its violation of the NPT. An official from Indonesia’s Ministry of Foreign Affairs, interviewed by the authors, emphasised that Indonesia’s stance has always been consistent with the NPT and that it opposes nuclear proliferation and armament. The official noted that if South Korea were to develop nuclear weapons, Indonesia would face significant issues in its broader relationship with South Korea, and would urge it to return to a non-nuclear weapon policy and uphold the principles of the NPT.^[15] An attempt to pursue nuclear weapons could cost Seoul its leverage and lead to isolation from the international community, including potential sanctions from other major powers.

Indonesia may want to prioritise its bilateral relationship with South Korea, considering its strategic and economic importance. However, if UN sanctions are imposed, maintaining those relationships could prove challenging. A precedent can be seen in 2019, when several countries imposed broad sanctions on Iran over its nuclear program and alleged human rights violations, causing trade between Indonesia and Iran to drop by 80.2%.^[16]

In the highly unlikely case that South Korea can proliferate without facing UN sanctions, Indonesia would likely be willing to maintain its bilateral relations with South Korea. Indonesia’s approach could reflect the country’s pragmatic realities of trade, business, and economic needs. South Korea remains a key investor in Indonesia, with foreign direct investment reaching approximately USD 2.5 billion in 2023 and bilateral trade reaching USD 20.8 billion in 2023.^[17] This hypothetical situation would likely create a potential divide within Indonesia’s bureaucratic elites.

While the Ministry of Foreign Affairs may advocate for upholding moral principles and international norms in line with its diplomatic agenda, other ministries, such as the Ministry of Industry and the Ministry of Trade, are likely to prioritise pragmatic economic considerations, pushing to maintain strong ties with South Korea to safeguard investments, especially in critical sectors such as infrastructure, energy, and technology to generate jobs and boost economic growth. However, the entanglement of nuclear proliferation issues with energy cooperation could mean that the MOU on SMR cooperation would be suspended, and Indonesia’s plans to build nuclear power would be in jeopardy.

Another potential implication of South Korea’s nuclear proliferation on the Indonesia-South Korea bilateral relationship is the concern that it could set a dangerous precedent in the region. While Indonesia has long advocated for nuclear non-proliferation, disarmament, and a nuclear weapons-free zone in Southeast Asia (SEANWFZ), there would be no guarantee that Indonesia would not feel compelled to explore nuclear capabilities in response to shifting power dynamics.

According to Dewi Fortuna Anwar, South Korea’s proliferation would not only cause a nuclear domino effect in Northeast Asia, with Japan feeling threatened, but it could also have a cascading effect on Southeast Asia, which would undermine the SEANWFZ and prompt countries in the region to consider developing their own nuclear technology. Such developments would significantly undermine the non-proliferation regime – if not destroy it altogether – complicate regional security, and heighten tension across the region. “The nuclear taboo will also be crossed. It’s not just Koreans who will cross the nuclear taboo; other countries will cross it as well. A taboo is only a taboo when you don’t do it. But once you start doing it, it becomes commonplace; it’s no longer a taboo.”^[18] For Indonesia, a nuclear-armed South Korea could present a direct challenge to its foreign policy objective of upholding the nuclear non-proliferation regime.

Countering South Korea’s proliferation

Indonesia and ASEAN are likely to take a strong stance against South Korea’s pursuit of nuclear weapons. As Indonesia has ratified not only the NPT but also the Treaty on the Prohibition of Nuclear Weapons (TPNW), it remains firmly committed to preventing the spread of nuclear weapons. South Korea’s potential pursuit of nuclear weapons would threaten the integrity of the NPT and global disarmament efforts. Therefore, Indonesia and ASEAN would strongly oppose any initiatives that undermine these international agreements.

The official from Indonesia’s Ministry of Foreign Affairs noted that Indonesia would definitely utilize ASEAN and all of the ASEAN mechanisms which South Korea is a part of, such as the East Asia Summit, ASEAN Plus Three, and perhaps ASEAN Plus One to encourage South Korea to return to a non-nuclear armed status and adhere to the principles of the NPT. It will also engage with multilateral forums, such as the UN and others, to do the same.^[19] Additionally, Dewi Fortuna Anwar expressed a desire to see the strengthening of trilateral cooperation not only between South Korea, Japan, and the US but also between South Korea, Japan, and China, in the hopes of improving South Korea-Japan relations and urging China to play a more active role in dialogue with Pyongyang.^[20] She elaborated:

“We need to continue toward political settlements. As long as North Korea feels insecure, it will continue to behave in ways it believes are necessary to protect itself. It’s not going to disarm its nuclear weapons because that’s the only leverage it has over the international community.

We in Southeast Asia don’t feel the need to possess such weapons because we’re not afraid of our neighbors, and we don’t perceive an existential threat to our national security. So, that’s what we need to push for: more dialogue, more cooperation, and more mutual trust.”^[21]

South Korea’s potential acquisition of nuclear weapons capabilities (or nuclear-powered submarines) would heighten regional tensions, destabilise the region, and challenge Southeast Asia’s nuclear-weapon-free zone. Considering these implications, the new Prabowo administration should demonstrate international leadership and engage proactively on nuclear non-proliferation issues. For Prabowo, regional stability is crucial if he is to meet his target of accelerating Indonesia’s economic growth to 8%. Drawing strength from Indonesia’s role within ASEAN and its long-standing commitment to non-proliferation, Prabowo should take a proactive stance by encouraging regional dialogue on the importance of strengthening the NPT. Prabowo, along with other ASEAN leaders, could also encourage South Korea (as well as Japan) to attend the TPNW Meeting of State Parties (MSP) in an observer capacity.

South Korea’s potential pursuit of nuclear armament would present significant challenges for its relations with Indonesia, a strong and consistent advocate of nuclear non-proliferation and regional stability, whose track record already suggests that it would strongly oppose any move by South Korea to develop its own nuclear weapons. While Indonesia may face internal debates about balancing diplomatic and economic ties with Seoul and adhering to non-proliferation principles, its overall stance would likely align with international efforts to prevent further nuclear proliferation. South Korea’s nuclearisation would also have broader implications for regional security, potentially undermining Indonesia’s vision of a nuclear-free Southeast Asia and prompting further instability in the Asia-Pacific.

For Indonesia, maintaining regional stability and the integrity of the global non-proliferation regime will remain a priority, even as it seeks to manage its bilateral relationship with South Korea. For South Korean policymakers, the question is whether they are ready to jeopardise their future relationship with an emerging major power in the region.

References

^[1] Victor Cha, “Breaking Bad: South Korea’s Nuclear Option,” Center for Strategic and International Studies (CSIS), April 2024, p. vi. https://www.csis.org/analysis/breaking-bad-south-koreas-nuclear-option.

^[2] KINU, “Result of the 2024 KINU Unification Survey,” Korea Institute for National Unification, June 27, 2024, https://www.kinu.or.kr/eng/board/view.do?nav_code=eng1678858138&code=78h7R6ucKsu M&idx=24481.

^[3] Lauren Sukin and Woohyeok Seo, “East Asia’s Alliance Dilemma: Public Perceptions of the Competing Risks of Extended Nuclear Deterrence,” June 2024, https://www.apln.network/projects/nuclear-weapon-use-risk-reduction/east-asias-alliance-dilemma-public-perceptions-of-the-competing-risks-of-extended-nuclear-deterrence.

^[4] Alexander M. Hynd, “Dirty, Dangerous… and Difficult? Regional Perspectives on a Nuclear South Korea,” Journal of Asian Security and International Affairs (Forthcoming).

^[5] Dewi Fortuna Anwar, interview with the authors, September 30, 2024.

^[6] Ministry of Foreign Affairs of the Republic of Indonesia, “Statement on Australia’s Nuclear-powered Submarines Program, Ministry of Foreign Affairs of the Republic of Indonesia, September 17, 2021, https://kemlu.go.id/portal/en/list/siaran_pers/105/statement-on-australias-nuclear-powered-submarines-program.

^[7] Joko Widodo, interviewed by Fiza Sabjahan, “Special Interview with Indonesia President Joko Widodo ahead of the 42nd Asean Summit,” New Straits Times, May 8, 2023.

^[8] MoFA Indonesia, https://x.com/Kemlu_RI/status/1635487836576292864, March 14, 2023.

^[9] BPMI of Presidential Secretariat/UN, “Indonesia, ROK to Enhance Strategic Partnership”, Cabinet Secretariat of the Republic of Indonesia, July 28, 2022, https://setkab.go.id/en/indonesia-rok-to-enhance-strategic-partnership/.

^[10] Indo-Pacific Defense Forum, “Indonesia, South Korea mark milestone with deeper defense collaboration,” Indo-Pacific Defense Forum, August 2023, https://ipdefenseforum.com/2023/08/ indonesia-south-korea-mark-milestone-with-deeper-defense-collaboration/.

^[11] Nam Hyun-woo, “Indonesia seeks cost cut, tech reduction in Korean fighter jet deal,” The Korea Times, May 2024, https://www.koreatimes.co.kr/www/nation/2024/10/113_374089.html.

^[12] Mi-ha Jeong, Seo-young Kim, and Mi-geon Kim, “Interview: ‘Indonesia is Land of Opportunity for S. Korea with Duty-Free Access.’” Chosun Daily, September 2, 2024, https://www.chosun.com/english/industry-en/2024/09/02/3KIDIMRVENAYXBVZDK5FRQJMUM/.

[13] “Indonesia Affirms Commitment to Paris Agreement at COP29,” Antara News, November 13, 2024, https://en.antaranews.com/news/333837/indonesia-affirms-commitment-to-paris-agreement-at-cop29.

[14] “South Korea and Indonesia Deepen Energy Partnership to Bolster Resource Security,” Korea PRO, November 13, 2024, https://koreapro.org/2024/11/south-korea-and-indonesia-deepen-energy-partnership-to-bolster-resource-security/.

^[15] Indonesian official at the Ministry of Foreign Affairs, interviewed by the authors, October 4, 2024.

^[16] Reuters, “Indonesia, Iran sign preferential trade agreement”, Reuters, May 23, 2023, https://www.reuters.com/world/indonesia-iran-sign-preferential-trade-agreement-2023-05-23/.

^[17] Sudibyo Wiradji, “Stimulating Indonesia’s economic growth through South Korean investment.” The Jakarta Post, May 21, 2024, https://www.thejakartapost.com/business/2024/05/21/stimulating-indonesias-economic-growth-through-south-korean-investment.html.

^[18] Dewi Fortuna Anwar, interviewed by the authors, September 30, 2024.

^[19]  Indonesian official at the Ministry of Foreign Affairs, interviewed by the authors, October 4, 2024.

[20] See: Dewi Fortuna Anwar, “ASEAN ‘Centrality’ and China-Japan-South Korea Trilateral Co-Operation,” Global Asia 19, no. 3 (September 2024), https://globalasia.org/v19no3/cover/asean-centrality-and-china-japan-south-korea-trilateral-co-operation_dewi-fortuna-anwar.

^[21] Dewi Fortuna Anwar, interviewed by the authors, September 30, 2024.

 

This paper was supported through a grant from the Heinrich Böll Foundation, and is part of a series that examines regional views of South Korean nuclear proliferation. The opinions articulated above represent the views of the author(s) and do not necessarily reflect the position of the Asia-Pacific Leadership Network or any of its members, or funders.

Image: Indonesia’s then-President Jokowi in a meeting with South Korean President Yoon Suk-yeol, at Yongsan Presidential Office, Seoul, 28 July 2022. (Photo: Bureau of Press, Media, and Information of Presidential Secretariat/Laily Rachev.)