NATO and the Republic of Korea: The AP4 in the Indo-Pacific

(Source: Official Website of the Prime Minister of Japan and His Cabinet,

In recognition of the growing importance of the Indo-Pacific, its economic and technological prowess, and against the background of the Sino-US rivalry, NATO has intensified its relationships with partners, the Republic of Korea (ROK or South Korea), Australia, Japan and New Zealand (AP4). Issues like nonproliferation, cyber defense, science and technology, counterterrorism, interoperability, defense against chemical, biological, radiological, and nuclear agents, as well as the hotspots of the Democratic People’s Republic of Korea (DPRK or North Korea), Taiwan, East and South China Sea, Myanmar and the border dispute between India and China, are all areas that can impact directly on the Euro-Atlantic security.

One of the reasons why it took the ROK seventeen years to accredit its Mission in Brussels to NATO (only in 2022) was that Seoul has focused for a long time mainly on the situation on the Korean Peninsula, where NATO was not perceived as an important player. The intensification of the Sino-US rivalry and the ROK’s goal to become a “global pivotal state”—that is, globally engaged and value-inspired—have changed this calculation, resulting in greater cooperation with NATO and individual member states.

This paper first sketches the rapprochement between NATO and the ROK because of geopolitical changes and the indivisibility of security. North Korea and nonproliferation, as well as cybersecurity, are uniting challenges and the need to factor China into the regional and global security equation. For the ROK, this means not only participation in sanctions against Russia but also backfilling much-needed weapons to Ukraine, where Russia uses North Korean shells. Strengthening more formal ties with NATO also serves as a preparatory measure if a transactional US president is returned to office; it can also contribute to rendering the bilateral relationship with Japan within the AP4 network more resilient. The paper concludes by pointing out that NATO needs public diplomacy in the Indo-Pacific to demonstrate its added value to security and diplomacy.

Participation in Summits

The ROK was invited for the first time to the NATO Summit in Madrid in 2022. There, it made a strong impression on both the military and value-sharing fronts. Boasting a defense spending of 2.7 percent of GDP—the Asia-Pacific partner outperforming many NATO members—and demonstrating solidarity in participating in sanctions against Russia because of its illegal war against Ukraine, these key elements and more made President Yoon Suk-yeol a sought-after interlocuter for those seeking to purchase arms at good quality and price at the summits.

The arms deal with Poland consisting of K9 self-propelled howitzers, K2 tanks, armored vehicles and aircrafts, including FA-50 fighter jets, amounted by 2023 to $11.7 billion, up 184 percent from a year earlier. This backfill operation for NATO members supplying Ukraine indirectly was appreciated by the alliance and strengthened the ROK’s positioning itself as a pivotal state in world politics. This policy shift was spurred by China’s “pro-Russian neutrality” and Russia’s growing engagement with North Korea, which also led the ROK to intensify cooperation with the US and warm up to Japan.

The division of and tensions on the Korean Peninsula are reflected in North Korea supplying the other party in the conflict, Russia, with artillery shells, leading to a situation where South and North Korean arms are used on the same battlefield. This is a peculiar situation for two countries where only an armistice reigns, reminiscent of past proxy situations. All at once, these deliveries by the North render a kinetic follow-up to Kim Jong Un’s fierce enemy rhetoric vis-à-vis the South unlikely as stocks are run down, although the probable Russian compensation in technological support for North Korea’s nuclear, weapons and satellite programs add to the tensions.

Reflecting the growing geostrategic interdependence, the NATO 2022 Strategic Concepts refer to the threat emanating from North Korea. “Iran and North Korea continue to develop their nuclear and missile programmes. Syria, North Korea and the Russian Federation, along with non-state actors, have resorted to the use of chemical weapons.” The NATO Secretary General also regularly issues statements, like on the occasion of “…the launch of a military satellite by the Democratic People’s Republic of Korea, using ballistic missile technology in violation of multiple U.N. Security Council resolutions. This raises tensions and poses a serious risk to regional and international security.”

NATO support for Seoul’s North Korea policy is a driving force for the ROK to cooperate with NATO. NATO supports denuclearization, condemns the North’s provocative rhetoric, nuclear activities and ballistic missile tests, and shares the view that this conduct poses a serious threat to regional and international peace, security and stability. The triangular arms delivery potentially contributes to standardization and interoperability among partners.

Cybersecurity is another common issue: As the ROK is often the victim of cyberattacks from China and North Korea, participation in NATO’s Cooperative Cyber Defence Centre of Excellence (CCDCOE) improves resilience; for the same reason, cybersecurity is also the pilot project for the European Union (EU)-ROK security cooperation.[1].

At the Vilnius Summit, the Individually Tailored Partnership Programme updated the previous one, specifying “in detail cooperation goals, the background of selecting areas for cooperation, strategic targets, detailed project content and implementation schedule to achieve cooperation.” The Vilnius Summit Communiqué deals with another main concern of the ROK, that is, China. It states: “The People’s Republic of China’s stated ambitions and coercive policies challenge our interests, security and values.” Therefore, while remaining open to constructive engagement, NATO allies will address “the systemic challenges posed by the PRC to Euro-Atlantic security and ensure NATO’s enduring ability to guarantee the defence and security of Allies.” While the ROK cannot expect any security guarantee from this arrangement, “shared awareness, enhancing our resilience and preparedness, and protecting against the PRC’s coercive tactics and efforts to divide the Alliance” as well as the plea to play a constructive role to end the war in Ukraine, are relevant for its security. While deterrence is achieved through the alliance with the US, the AP4 relationship may add to it, if consultation with the US actually shapes its policies and strategic choices.

Need for a Credible “Out-of-Area” Agenda

The Indo-Pacific remains “out-of-area” for NATO; however, “situational awareness of security developments in the Euro-Atlantic and Indo-Pacific regions, including Russia’s war on Ukraine, the shift in the global balance of power and the rise of China, and the security situation on the Korean Peninsula” are of mutual importance, recognizing that there is only one comprehensive security. Therefore, the transatlantic and the transpacific dimensions need holistic evaluation and response.

This also applies to the EU, which recognizes that:

A paradigm shift towards more realism without throwing idealism overboard is in the making, which needs conceptual work as started with the Strategic Compass and close cooperation in the Transatlantic and Transpacific theatres with the US and interested partners.

The Strategic Compass specifies that the EU will deepen and expand the “strategic partnership, political dialogue and cooperation with NATO across all agreed areas of interaction, including new key work strands such as resilience, emerging disruptive technologies, climate and defence and outer space.” While the Korean engagement with NATO provides an additional opportunity for comprehensive cooperation between Brussels and Seoul, EU and NATO operations are different and should be kept separate, such as Operation ATALANTA and Operation Ocean Shield.

The informal NATO framework of AP4 cooperation has also helped the rapprochement between Japan and the ROK, providing stepping stones for quadrilateral meetings leading to the trilateral Camp David Summit, the Camp David Principles and the Commitment to Consult. Japan and the ROK are invited for the third time in a row to the 2024 July NATO Summit in Washington. As part of this summit, a trilateral meeting in the Camp David format is under preparation to keep the momentum. This will be necessary to keep historic issues at bay. Recent decisions by the Korean Supreme Court in favor of wartime forced labor workers’ claims on Japanese companies could strain the relationship. However, for the first time ever, a Japanese company paid compensation to the family of a deceased worker,  which is potentially an important step in solving the issue and essential for being able to sustain ROK-Japan ties amid the aggravating security situation. In terms of security, the trilateral will serve to discuss further cooperation in the context of NATO and find common ground on North Korea, as Japan seems to be interested in holding a summit meeting.

NATO also plays a role in the context of nonproliferation. Considering the threats emanating from North Korea and China, the ROK’s trust in the iron-clad alliance with the US started to crack during President Trump’s “love affair” with the North Korean leader. Doubts about the US nuclear umbrella fueled discussions in Seoul about “nuclear sovereignty,” that is, the indigenous production or stationing of US nuclear arms in the ROK. In this context, NATO-style weapon sharing, which means participation in the planning of deterrence, could reduce the temptation to go alone. At the occasion of the 70th anniversary of diplomatic relations in 2023, the US and the ROK agreed to the Washington Declaration, where Seoul confirmed: “full confidence in U.S. extended deterrence commitments and recognize the importance, necessity, and benefit of its enduring reliance on the U.S. nuclear deterrent.” This reassurance should help President Yoon to stand his ground.

However, future developments will depend heavily on the US and its policy towards the ROK: gaining operational control (OPCON) over the military in times of war is an unresolved issue that nourishes the nationalistic undercurrent. The same goes for Seoul’s contribution to burden sharing for US troops stationed in the country (Special Measures Agreement), where President Trump previously pushed undiplomatically and hard for a major increase. These elements could become a push factor for Seoul to strive for nuclear sovereignty. Its diplomatic costs in breaching nonproliferation agreements, the likely spreading of proliferation to include Japan, would need to be weighed against security gained—all negative, in my opinion.

As a return to a transactional US presidency is of concern, there are also efforts underway to strengthen institutional bonds to increase the resilience of US engagement. This was also the main theme of the 75th anniversary meeting of NATO foreign ministers in Brussels in April 2024; as Secretary General Stoltenberg put it, “I do not believe in America alone. Just as I don’t believe in Europe alone. I believe in America and Europe together.” AP4 foreign ministers were invited and had a separate working session with their NATO colleagues.

NATO’s outreach to AP4, in addition to the intelligence network Five Eyes, Quad and eventually Quad+, AUKUS, D-10 Strategy Forum of leading democracies, the Summit of Democracies, and T-12 Techno Democracies could change the US hub-and-spoke alliance system into a more network-based system, establishing links among the various bilateral and minilateral arrangements. The planned trilateral US-Japan-Philippines military exercise is part of this new development. Nevertheless, there is a similarity between the US and China in their strategic approach to their rivalry: both prefer setting up their own arrangements instead of working through existing ones, like the United Nations or G20—a great power attitude to apply strengths directly and unfiltered.

Already before Xi Jinping, the Shanghai Five became the Shanghai Cooperation Organisation (SCO) and the Conference on Interaction and Confidence Building in Asia (CICA) was meant to provide a vehicle for an “Asia for Asians” policy. The Boa Forum, BRICS+, the New Asia Development Bank, the Asia Infrastructure Investment Bank (AIIB) and various funds supporting the Belt and Road Initiative (BRI) are further examples, as well as China’s participation in regional free trade agreements like Regional Comprehensive Economic Partnership Agreement (RCEP) and its interest in joining the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP).

In contrast, the US or, more specifically, President Trump, dropped out of the Trans-Pacific Partnership (TPP) in 2017. Instead of rejoining that regional trade arrangement, President Biden opted to pursue his own, albeit less ambitious, initiative, the Indo-Pacific Economic Framework for Prosperity (IPEF), which has a strong like-minded element but—crucially—does not grant market access. While these cooperative efforts restrain bilateral pressure, they contribute to a bifurcation of global political and economic systems as the guardians of the systems, the UN and World Trade Organization (WTO), are weak.


The ROK’s engagement with NATO provides a platform and network for building a more comprehensive security policy. The AP4 share interests in keeping the US engaged in the Indo-Pacific, to which deliberations in and with NATO can contribute. While also driven by commercial considerations, Korean arms sales to Poland have contributed to NATO’s efforts to support Ukraine in its legitimate defense. These sales offer an additional alternative sourcing, thereby also contributing to de-risking in a situation where Europe has problems supplying promised armaments, the US Congress is paralyzed by the stand-off between Democrats and Republicans, and Trump II is looming. In addition, and importantly, at the interface of civil-military technology, the ROK is leading in high-end semiconductors, which is also of interest for the European defense industry.

Seen from the EU perspective, the ROK is on the same page concerning rule of law, reform of trade governance and a cooperative stance in the Indo-Pacific, including China. They share the view that economic and technological security cannot be achieved by decoupling but needs careful management to achieve the goal of greater resilience. A transatlantic and transpacific network of partners resolute to maintain a rules-based order strengthens the individual partners and networks. This also adds to deterrence when presented realistically.

In this context, getting the evaluation of security developments in the Indo-Pacific from the AP4 based on their onsite intelligence and regional experience is a strategic asset for NATO. Openness for all those interested in cooperating according to rules could contribute to the stabilization of the Indo-Pacific and counter the narrative of encircling China. It reflects that security has become indivisible, as NATO Secretary General Stoltenberg underlined at the occasion of the 75th anniversary foreign ministers meeting, albeit more from a European perspective:

…the war in Ukraine demonstrates how intertwined the security of Europe is with the security of Asia and the Pacific. North Korea, China, Iran are supporting Russia’s war of aggression in different ways, so this demonstrates that security is not regional security, it’s truly global, and therefore it is important that we work together with our Asia-Pacific partners.

At the same time, experience in the post-Soviet era teaches us that it is crucial to avoid any misconception of NATO’s engagement in the Indo-Pacific. French reluctance to agree to a liaison office in Tokyo was also inspired by the concern not to irritate China further—a valid point in expectation management. NATO support for the ROK’s policy of the denuclearization of North Korea and nonproliferation is less sensitive for China. China has been the nearly only backer of North Korea for decades. Thus, the marriage of convenience between Russia and North Korea, which reduces Chinese influence, is not to China’s liking in the long run. As the US regards North Korea as the more immediate threat and China the long-term systemic rival, cooperation on North Korea could become a common cause. Similarly, Japan and Korea focusing on North Korea could help soothe China, which otherwise eyes this new entente with suspicion and as part of a US-lead containment policy.

Given the discussed minilateral as well as the underlying bilateral strategic partnerships, agenda setting for the various institutions and meetings is important in choosing the appropriate forum, especially in terms of inclusiveness and transparency and avoiding ineffective overlaps. For NATO, this means developing an agenda showing added value in combining transatlantic and transpacific strategies to meet threats in both theatres beyond the acute menace, based on mutual interest, to engage partners sustainably. Thus, there is a need for public diplomacy, explaining mutual benefits, especially for preserving peace in the region, as general publics are not familiar with NATO’s tasks. Preventive diplomacy to maintain peace and make sure that Ukraine is not tomorrow’s Taiwan would be in high demand.

  1. [1]

    Gertjan Boulet, Michael Reiterer and Ramon Pacheco Pardo, eds. Cybersecurity Policy in the EU and South Korea from Consultation to Action: Theoretical and Comparative Perspectives (London: Palgrave, 2022).

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