In light of these geopolitical transformations, one of the main concerns that unites these three actors is the rise of powers that question the status quo in Europe and Northeast Asia. In particular, there is the fear that the war in Ukraine constitutes the free and open international order’s atrophy. Producing smart responses to moves by Russia and North Korea are therefore considered central against this background. Moreover, China and the United States are two important actors to consider. Under Trump’s leadership, the latter’s commitment to the international order appears increasingly inconsistent and unpredictable. This not only challenges the survival of the status-quo in terms of security, but also leaves a reference gap that the European Union, Japan, and South Korea (the Republic of Korea or ROK) could fill together.
Reacting to Russia: Uniting the EU, Japan and South Korea
Firstly, as concerns Russia, the outbreak of the war in Ukraine in February 2022 came as a shock to many European powers, majorly impacting the European continent and Ukraine itself. With more than 12,000 civilian casualties and over 5.6 million refugees across Europe, the conflict has influenced how Russia is perceived as a geopolitical actor. Already before the invasion in 2022, Moscow had been acting increasingly assertive, as seen, for instance, in Georgia in 2008 or with the escalation of tensions after Moscow’s unilateral adhesion of the Ukrainian Crimea in 2014. In the past few years, the Kremlin has also been accused of meddling in elections in neighbouring states, such as Moldova or Georgia, while still being entangled in an ongoing territorial dispute with the latter. Moreover, Russia is under investigation for using hybrid tactics to influence elections in EU member states, such as Romania, while some MEPs suspect a similar incident during the European Parliament’s 2024 elections.
Russia’s invasion of Ukraine has been a notable turning point in the EU, Japanese, and South Korean defence outlooks. All three have condemned Russia’s actions and implemented related sanctions. Albeit being a conflict on European soil, it is also widely seen as an attack on the rules-based international order, of which the EU, Japan and South Korea have been strong, long-time promoters. Since the beginning of the war in Ukraine, the EU has sought to limit its energy dependency on Russia by diversifying gas imports, advancing EU accession talks with Ukraine and Moldova, and supporting military cooperation and supply to Ukraine, amongst other measures. The conflict has also revived the relevance of NATO as an alliance, prompting the European countries Sweden and Finland to join it.
Following the outbreak of the war, the Japanese government provided Ukraine with military equipment and humanitarian assistance. Tokyo has also committed to strengthen its ties with Kyiv. Moreover, in December 2022, Tokyo published its new National Security Strategy, National Defence Strategy and Defence Buildup Programme. These announced a significant increase in military spending, alleging that Japan is facing the “most severe and complex security environment” since the end of World War II. The government stated that the “free, open, and stable international order” is at stake, asserting the situation in Ukraine to be a breach in “the very foundation of the rules that shape the international order.” In his April 2024 address, former Prime Minister Fumio Kishida reiterated this message, declaring that “[the] Ukraine of today may be [the] East Asia of tomorrow.”
South Korea’s foreign policy took a more assertive stance after Yoon Suk-yeol’s election as President in 2022 while strongly emphasising Seoul’s commitment to the liberal international order. In its 2022 Indo-Pacific Strategy, South Korea announced its intention to become a “global pivotal state”. Through its rapidly expanding defence industry the country has been a major arms supplier since the outbreak of the war, supporting the Ukrainian defence through provisions supplies to Central and Eastern European countries such as Poland, Romania and Estonia.
Overall, the war between Russia and Ukraine has united the three actors, constituting a common denominator in their defence and security outlooks. Despite their geographical distance, they are geopolitically close in values, considering the outbreak of the war as a substantial threat to the international order. This situation has been exacerbated by other states’ reactions to the event, forging new alliances or altering their existing relationships, like North Korea’s deepening ties with Russia, China’s response to the conflict, and the US’s unpredictable support for the global multilateral order and pertaining uncertain security provisions under Donald Trump’s second presidential term.
North Korea’s Ties to Russia: Uniting the Three Actors in Northeast Asia
A second factor in the geopolitical landscape uniting the EU, South Korea and Japan is North Korea. The Democratic People’s Republic of Korea (DPRK) has long worried neighbouring countries in the region due to its evolving nuclear arsenal, frequent firing and testing of missiles, and the announcement of the creation of an underwater nuclear drone in the Sea of Japan. In 2024, Kim Jung-Un announced to no longer pursue the goal of unifying the Korean Peninsula, calling its neighbour South Korea a “hostile state.” Therefore, the security situation on the Peninsula with North Korea is delicate, concerning both Japan and South Korea. Moreover, the DPRK’s military involvement in Ukraine has also made North Korea a direct worry for the European Union. Pyongyang’s aid constitutes North Korea’s first major involvement in a conflict since the 1950-53 Korean War, and the largest shipment to date of anti-tank missiles, short-range ballistic missiles, rocket-propelled grenades and millions of artillery shells to Russia. As of March 2025, the country has also deployed more than 11.000 soldiers to fight on Moscow’s side. In return, Russia has sent North Korea conventional arms and technology in support of its plans to deploy spy satellites.
Russia-North Korea ties worry the European Union, South Korea, and Japan. Making the link between the two actors explicit, North Korean troops siding with Russia in its war with Ukraine has been a significant game-changer. During their June 2024 summit, Kim Jong-un and Vladimir Putin signed a “comprehensive strategic partnership.” As Pyongyang helps provide military manforce, fears are arising of the Kremlin helping modernise North Korean intelligence, technology and advancing its (nuclear) armament. These developments are a reminder of the intertwined security concerns bridging Europe and Northeast Asia.
China
A third actor in Northeast Asia to consider is China. Establishing itself as a global power, the People’s Republic of China (PRC) has developed -and partially implemented- a distinct security concept for the Indo-Pacific. This includes the expansion of its own multilateral and security dialogue formats, the comprehensive rearming of the People’s Liberation Army (PLA), and the militarisation of the South China Sea through the deployment of China Coast Guards (CCG). As a result, China’s military and naval expansion has raised concerns in Japan and South Korea.
As regards the war in Ukraine, the PRC has supported a peaceful resolution to the conflict but has not directly condemned or supported any party. However, it has been engaged with Russia in a “no limits” partnership, offering Moscow economic and political support. In response, the EU has expressed its concerns over China helping Russia to circumvent sanctions. This strengthened Sino-Russian engagement has thus become a security concern for the EU, Japan and South Korea. Other security considerations include Japan’s territorial dispute with China over the Senkaku/Diaoyu Islands, concerns over espionage in EU member states, or the development of advanced Chinese technologies that could be applied for dual use and military purposes. Security in the Taiwan strait is also a matter of concern for the three parties, as a considerable share of their trade passes through the area, with the EU being the Island’s 4th largest trading partner and Japan and South Korea occupying the fourth and fifth place respectively in single-country reports.
Despite these considerations, the substantive trade relationship between the three Northeast Asian actors, as well as long standing diplomatic ties are not to be disregarded. China’s trade with both Japan and South Korea holds much higher figures than the US. Diplomatic exchanges between the three partners are also established, like for instance the Trilateral Foreign Ministers Meeting between China-Japan-South Korea. These factors thus play a not to be dismissed role in the defence and security dynamics of Japan and South Korea.
Unpredictability Stemming from Donald Trump’s “America First” Strategy
The fourth and last key factor in the region is the US and its current foreign policy and security provisions. Donald Trump’s return to the White House has fueled concerns about US commitment to the free and open multilateral order. In the defence sphere, the 14 February 2025 Munich Security Conference was a clear testament of Washington’s changed commitments. US Vice President James David Vance’s speech enhanced the conversation about EU over-reliance on the US for defence, particularly through NATO. Since then, the EU has been gearing up, announcing to mobilise up to 800 billion EUR to bolster defence on the continent. Recently, the Union also published its White Paper for European Defence, focusing on three areas of action: closing capability gaps, deepening the single defence market, and enhancing European readiness for worst-case scenarios.
While European powers rank high in the US military out of territory bases, in the Indo-Pacific, Seoul and Tokyo host the world’s first and third largest US military troops (Germany ranking second). Washington’s plans generate uncertainty about the White House’s security engagement with its Asian and European counterparts. For now, cooperation with Japan seems to hold despite the recent developments concerning US tariffs. However, an official summit or high-level meeting between Seoul and Washington has yet to take place, fueling concerns about potential shifts in alliance priorities. There is growing concern that the US may prioritise deterring China, which would impact South Korea’s primary security concern, the DPRK.
Both Asian countries have thus far avoided confrontation vis-à-vis the imposed US tariffs of 24% (Japan) and 25% (Korea) respectively. Overall, there is a perceived sense of urgency in filling the gap that the US is leaving behind, upholding the liberal and rule-based international order. Although there is a momentum prompting the three partners to act together, the most difficult question might be to find concrete avenues of cooperation.
Understanding Existing Security and Defence Ties Between the EU, Japan and the ROK
So far, the EU, Japan, and the ROK have some common security-related activities, mainly through NATO and other bilateral agreements. The NATO Alliance is where most joint military engagement takes place, thanks to the bilateral Tailored Programs Partnerships and the IP4 framework, even more so now that the Alliance is shifting its focus toward the Asian and Indo-Pacific region. In 2019, NATO first declared that China’s growing influence posed “challenges”, becoming more explicit in wording over the years. In 2022, the NATO Strategic Concept, the Alliance’s core document, mentions the importance of the Indo-Pacific, highlighting that “developments in that region can directly affect Euro-Atlantic security.”
Around the same time, both Japan and South Korea began closer cooperation with NATO under the current IP4 framework. This alliance enhances the Transatlantic cooperation with Japan, South Korea, New Zealand and Australia, promoting joint initiatives. Although geographically distant from NATO members, these countries share a common interest in upholding the rules-based international order. Therefore, NATO cooperation with these countries primarily focuses on “enhancing situational awareness of security developments […] including Russia’s war of aggression against Ukraine, the People’s Republic of China’s (PRC) stated ambitions and coercive policies in various domains, the deepening strategic partnership between the PRC and Russia, and the security situation on the Korean Peninsula.” For instance, during the 2024 Washington summit, they agreed on “flagship projects” supporting Ukraine on military healthcare, as well as cooperation on cyber defence, countering disinformation, and advancing technology.
Figure 1. Compiled by the author based on NATO sources.
Outside of the North Atlantic Treaty Organisation, the EU, Japan and South Korea have not engaged in many trilateral activities thus far. Their cooperation remains limited to bilateral agreements and cooperation. In recent years, the EU has signed digital partnerships and security and Defence Partnerships with both Japan and South Korea, which focus on the exchange of information, cyber cooperation, research and study on hybrid threats, among other similar domains. In particular, defence cooperation seems to be more developed with South Korea, being the only Asian country part of CSDP missions, in particular, the EUNAVFOR Atalanta. Nevertheless, Japan is planning to contribute to that mission in the future, specifically through the Administrative Agreement (AA).
As indicated in the graph below (Figure 2), there is a clear overlap between the EU’s engagement with Japan and South Korea, having concluded similar agreements in the past years. Yet, besides through multilateral frameworks, there are no trilateral joint initiatives to date.
Figure 2. Compiled by the Author based on sources from the European Parliament Research Service
In terms of bilateral cooperation, Japan and South Korea normalised their military relationships at the 2021 Shangri-La Dialogue. In recent years, most of their bilateral engagement has transpired through trilateral cooperation with the US. Notably, the three countries have signed the Camp David Principles (2023), the Trilateral Economic Partnership (2024), and the Trilateral Security Cooperation Framework (2024). However, the White House’s current approach towards the Indo-Pacific is expected to lower the trilateral engagement shown until now.
A final component to understanding EU-Japan-South Korea trilateral cooperation is their respective domestic political situations. First, given its design, the European Union’s policy-making process can sometimes be slow, while in security-related matters, the incentive to cooperate is more urgent. This policy area is currently expanding at the overarching EU level, as it remains a Member States competence. However, it may take time to be further defined and coordinated between the EU27. Second are domestic challenges, as the government’s fragility and political uncertainties in South Korea and Japan may inhibit the success of their intended global presence and role in international relations. In South Korea, former President Yoon Suk Yeol’s impeachment and upcoming Presidential elections on 3 June 2025 make Seoul’s future role on the global stage harder to predict. In Japan, Shigeru Ishiba’s minority government remains fragile, impacting the decision-making process.
Potentials for enhanced EU-Japan-South Korea trilateral cooperation
There are many commonalities uniting EU, Japanese, and South Korean geopolitical interests. Firstly, they share similar perspectives and worries, as highlighted in their security outlooks. The rise of powers questioning the multilateral order is of growing concern, a risk overtly manifesting since Russia’s invasion of Ukraine in 2022. Secondly, Brussels, Tokyo, and Seoul are affected in similar ways by the alliances formed since the start of the war, markedly the North Korean-Russian partnership, China’s engagement with Russia and military build-up in the Indo-Pacific, and the unpredictable role of the US in defence procurement. How to effectively interact and react to this remains the central question.
For South Korea and Japan, defence-wise, the European Union cannot replace or be on par with the US in the short term. These countries have a shared history and long standing relations with the North American power, which explains their close cooperation. However, there is a growing opportunity to strengthen the ties and the momentum is building to establish a formal trilateral EU-Japan-South Korea framework. As seen in Figure 2, both Asian countries have walked a similar path with the EU in recent years, having concluded almost identical, parallel agreements and partnerships. Therefore, Brussels could further enhance its existing platforms with Japan and Korea, not only bilaterally but also through trilateral agreements and initiatives. The Security and Defence and the Digital Partnerships form perfect starting points to tackle not only defence matters but also to move beyond this domain and work closer together in other areas concerning, for instance, economic security, climate change and sustainable development. Similarly, the NATO IP4 framework should continue to be supported, strengthening European security and deepening inter-regional collaboration. Although it might take time to develop such a framework, the establishment of regular trilateral summits could be a good start.
In today’s volatile and unpredictable world filled with uncertainties, the European Union, Japan and South Korea should continue to expand their partnership, bilaterally and in a trilateral way. What is more, the void left by the United States could be filled by further coalition-building between like-minded partners in other matters. Closer engagement between Japan, South Korea, and the European Union could build the foundation of a larger multilateral cooperation framework to include the other IP4 states Australia and New Zealand, EFTA countries, Canada, and beyond.
Author: Vera Rodríguez Corcho, EIAS Junior Researcher
Photo credits: Pexels
