South Korea faces growing vulnerability as US resolve wavers across Asia and Europe alike, most starkly on the volatile Korean Peninsula. After June 2026 EU-South Korea summit's pledge to deepen their strategic partnership, it's time for both sides to act, turning shared commitment into concrete steps that strengthen mutual security.
Asia is a focal point of US–China competition: while China seeks regional primacy, the United States seeks to retain its leadership role. Since taking office, however, the administration of US president Donald J. Trump has shown signs of declining capacity and resolve to sustain that role. A similar pattern is evident in Europe, where a Pentagon review of American troops on the continent is currently underway, along with force reductions already announced. In Asia, this weakening of US leadership is creating openings others could exploit.
These trends are particularly evident on the Korean Peninsula, one of the region’s most dangerous flashpoints, with South Korea being among the most vulnerable to a shift in the regional balance. South Korea and the EU should therefore move beyond merely recognizing the growing connection between Asia and Europe. In June 2026, at the EU–Republic of Korea (ROK) summit, both sides committed to taking their strategic partnership forward. Now, it is time to act on that commitment to enhance the security of both.
In-decent peace?
How the US is losing the diplomatic initiative
The latest US strategy documents have defined the Trump administration’s approach to competition with China in terms of a ‘decent peace’. Unlike during his first term, when his administration framed China as a strategic competitor and confronted Beijing across the economic, technological, military and ideological domains, Trump now appears more interested in managing competition and avoiding direct confrontation.
This approach was particularly evident at the Trump–Xi summit in May 2026. At Chinese president Xi Jinping’s suggestion, the two leaders agreed on a new vision for a ‘constructive bilateral relationship based on strategic stability’. As observers noted, this left the rest of the world wondering ‘whether U.S.-China “strategic stability” will restrain rivalry, conceal it, or turn it into a bilateral bargain over their heads’.
China appears to interpret the phrase as a reinforcement of its longstanding position on Taiwan. Xi stated that the ‘Taiwan issue is the most important matter in China-U.S. relations,’ adding that ‘if it is handled incorrectly, the two countries could collide or even clash, leading to a highly dangerous situation’. Experts predicted Xi would press Trump to delay or reduce arms sales to Taiwan. After the meeting, Trump told reporters that he had discussed Taiwan arms sales ‘in great detail’ with Xi. He later told Fox News that those sales were a ‘good negotiating chip’ in dealing with Beijing.
Their discussion of Taiwan raised a lot of concerns – and it carries implications for South Korea. If Trump appeared willing to treat even Taiwan – the most pressing security issue between China and the United States – as negotiable, this put its overall reliability into question. Indeed, the United States appeared to have made little progress in persuading China to support its goal of North Korea’s denuclearization. Trump and Xi reportedly exchanged views on the Korean Peninsula, but the initial official readout made no mention of either the Korean Peninsula or North Korea. Only in a supplemental fact sheet released several days later did the White House claim that Trump and Xi had ‘affirmed their shared objective of denuclearising North Korea’.
In short, the United States may formally retain its existing policy positions on Taiwan and the Korean Peninsula, but it is losing the diplomatic initiative needed to advance them. Washington has left too much room for others to reshape the diplomatic agenda.
How the US is losing its military foothold
At the same time, the US military presence in the Pacific is under growing strain. The immediate cause is the US’s war with Iran. Since the Obama administration, successive US governments have described the Indo-Pacific as the country’s priority theatre. Yet efforts to pivot toward Asia have repeatedly been disrupted by crises in the Middle East.
As the Iran war has dragged on, it has placed further pressure on already limited US stocks of missile defence interceptors. General Xavier Brunson, commander of US Forces Korea, confirmed during a hearing that the United States transferred some THAAD (Terminal High Altitude Area Defense) interceptors to the Middle East. The Pentagon has also diverted Patriot (PAC-3) interceptors, along with certain support equipment and interceptor missiles previously assigned to US Forces Korea.
South Korea has borne a significant share of the cost. South Korean and US military authorities also cancelled the Ssang Yong joint amphibious exercise, originally scheduled for September 2026, because the Middle East security situation had constrained the availability of the forces required for the exercise. Also, US officials said that the US military was deploying the USS George Washington, stationed in the Western Pacific, to the Middle East to replace the USS Abraham Lincoln.
The lessened US presence leaves a vacuum when it comes to maritime power projection. This holds particularly true for Korea’s West and East Seas. Meanwhile, contestation continues in the South China Sea, where China has just completed the first phase of land reclamation for a massive artificial island.
Adversaries align
China, Russia and North Korea have been expanding their respective bilateral ties. Both China’s and North Korea’s relations with Russia have grown considerably stronger since the onset of Russia’s war in Ukraine. At their May 2026 summit, China and Russia jointly affirmed the positive significance of China’s vision of building a ‘community with a shared future for mankind’. This was followed by a June 2026 Xi–Kim Jong Un summit, in which North Korean leader Kim Jong Un also endorsed Xi Jinping’s vision, stating that it held profound significance for promoting world peace and development.
Their growing diplomatic solidarity, as well as their bilateral arms network, is narrowing the room for manoeuvre available to South Korea and other countries. Trump has done little to develop an effective response. On the contrary, Trump has touted his personal relationship with Kim Jong Un, while also emphasising that North Korea is a nuclear power.
This has fuelled a growing debate over whether US allies and partners should seek ways to protect themselves without the United States. Elbridge Colby, Under Secretary of War for Policy, dismissed that the idea of middle power networks excluding the United States, saying that they would be ‘fashionable but superficial’. Yet this argument also reflects anxiety that such networks are already beginning to emerge.
South Korea’s China dilemma
Against this backdrop, the US administration has cast doubts on its reliability as an ally. Its commitment to providing extended deterrence to South Korea against North Korean military threats is increasingly being called into question. At the same time, Washington has shown that it may lack the capacity to respond effectively to conflicts unfolding simultaneously across multiple regions.
Meanwhile, the South Korean government wants to maintain stable relations with China. Seoul is pursuing a more national interest–centred approach, which it calls ‘pragmatic diplomacy’. This strategy seeks to strike a better balance in navigating US–China competition, marking a departure from the previous administration’s strong emphasis on relations with the United States.
There are two main reasons why the current South Korean government believes that better relations with China serve the national interest.
First, as South Korea’s largest trading partner, China has considerable economic leverage over South Korea. A decade ago, Seoul experienced significant economic retaliation from Beijing after agreeing to host the US THAAD system on its soil. That memory continues to shape its approach towards Beijing.
Second, China is North Korea’s only formal ally. Many in South Korea believe that maintaining decent relations with Beijing will discourage it from adopting policies too heavily tilted toward Pyongyang. There is also hope that China might exercise at least some control over North Korea in ways favourable to South Korea.
What Seoul is overlooking, however, is that closer relations with China also come at a cost.
First, information security remains a concern. For instance, although Chinese products are widely used in South Korea, the use of Chinese-made equipment in the military raises questions about potential security risks for South Korea. Differences in political systems and approaches to individual rights, along with China’s formal alliance with North Korea, are likely to remain sources of caution for Seoul. Also, some Chinese companies’ terms of service include provisions allowing for active monitoring of users when necessary for China’s national interests.
Second, South Korea may find itself on the sidelines of some US-led trilateral and minilateral arrangements. Even as Washington calls for greater responsibility and burden sharing from its allies, it is developing smaller security groupings in response to shared concerns about China. Ely Ratner’s proposed ‘Pacific Defense Pact’, for example, did not include South Korea. Seoul was also absent from an intelligence-sharing coalition that emerged around Balikatan, the recently held exercise in the Philippines described as the largest in its history.
Third, Seoul’s efforts to maintain stable relations with Beijing may partly explain its cautious response to China’s grey-zone activities. Illegal fishing by Chinese vessels remains a concern, and only one of the disputed Chinese installations in the Provisional Measures Zone (PMZ) has been removed. Cases of suspected espionage involving Chinese nationals have also prompted concerns, which raise questions about whether Seoul’s response has been sufficient to address the risks.
The longer South Korea remains caught in this dilemma, the greater the risk that it will lose the trust of both sides, the United States and China. Neither side has much patience or strategic room to spare.
South Korea therefore needs to find its own way out of this dilemma. It should establish clearer principles and criteria for deciding when, how and with whom to cooperate amid a shifting global order.
South Korea’s ‘why’ question
The first factor Seoul must consider is how its most serious security threat is changing. North Korea is deepening comprehensive cooperation with Russia that extends well beyond the military sphere, and it appears interested in making friends and joining a regional organization such as BRICS or CSTO. These developments suggest that Pyongyang is using China and Russia to expand its international presence.
The second factor to consider is values. South Korea developed and prospered within an order built around values upheld by the United States. A democratic political system, the rules-based international order and non-proliferation have also become part of South Korea’s own identity. The weakening of America’s ability (and resolve) to stand up for these values does not necessarily mean that South Korea no longer needs to uphold them. On the contrary, now that South Korea is considerably more capable than it once was, it may be time for Seoul to consider taking a more active role in backing liberal values.
Finally, South Korea should consider that even if it brings significant strengths to the table, it needs cooperation with other countries. It has highly capable armed forces and world-leading technologies in semiconductors, shipbuilding and information technology. It also possesses enormous cultural assets, collectively known as K-culture, spanning film, music, fashion and beauty. At the same time, however, South Korea needs to strengthen its naval and air military capabilities and cannot adequately address challenges in cyberspace without international cooperation. Technological cooperation with like-minded countries is also essential with regard to advanced technologies such as artificial intelligence.
South Korea and Europe: from shared interests to joint action
Taken together, these considerations suggest a logical partner for South Korea: Europe. Increased cooperation between South Korea and the EU, as well as its Member States, is more than simply desirable. The two sides share an interest in preventing further attempts by revisionist powers to undermine a rules-based global order. South Korea also has both a national identity and strategic interests that give it reason to help uphold the values traditionally defended by the United States. It is therefore time to move beyond merely recognizing the growing connection between Asia and Europe. At the 2026 EU–Republic of Korea summit, they reaffirmed their commitment to their strategic partnership. Now, they need to move on implementation.
Institutional support will be essential to making cooperation with Europe more concrete. The second ROK–EU Security and Defence Dialogue was held in May 2026, co-chaired on the South Korean side by director-general–level officials from the Ministry of Foreign Affairs and the Ministry of National Defence. The two sides should consider elevating this dialogue to a vice-ministerial level 2+2 format. This could create greater scope for decisive cooperation in areas where South Korean and European interests converge, moving the relationship beyond largely formal exchanges.
Cooperation between Europe and the Indo-Pacific Four (IP4), namely South Korea, Japan, Australia and New Zealand, should also be strengthened, while being complemented by bilateral engagement between South Korea and individual European countries. South Korea’s understanding of Europe remains limited, particularly when it comes to the distinct characteristics of individual EU countries. This knowledge base needs to be broadened. Developing as many channels of contact and levels of engagement as possible would help build a deeper relationship. Individual European countries should take the initiative in seeking Track 1 and Track 2 engagement with South Korea, and South Korea should make corresponding efforts to reach out to them.
South Korea and Europe should focus, in particular, on areas in which cooperation can overcome geographical constraints, including non-proliferation, space, cybersecurity, and foreign information manipulation and interference (FIMI). These are also areas in which China, Russia and North Korea – countries that challenge both South Korea and Europe – are cooperating most actively. Such areas offer an especially practical basis for cooperation because South Korea and Europe differ somewhat in their threat priorities: South Korea sees North Korea as its primary threat, while Europe places Russia first, although both regard China as a major secondary challenge.
Finally, European countries can deepen cooperation with South Korea by participating more actively in sanctions enforcement against North Korea. As Pyongyang expands its military cooperation with Moscow, constraining North Korea would also help limit the threat posed by Russia to Europe. At present, only five European countries – the United Kingdom, France, Germany, Italy and the Netherlands – participate in the Multilateral Sanctions Monitoring Team (MSMT), which was established to fill the gap left by the UN Panel of Experts, officially disbanded in April 2024 due to Russia’s veto. More European countries should join this effort and help constrain North Korean activities that violate the rules-based international order.
Thus, the case for closer ties between South Korea and Europe is strong. It’s time to realise the potential.
The views and opinions in this article do not necessarily reflect those of the Heinrich-Böll-Stiftung European Union | Global Dialogue.
