How will South Korea navigate US-China competition in 2025?

Growing strategic competition between the United States and the People’s Republic of China (PRC) has ended the era when South Korea could enjoy both a robust trade relationship with China and a strong alliance with the United States. We have come a long way since President Roh Moo-hyun (2003-2008), an exemplar of such thinking, called South Korea a regional “balancer” that would navigate a path between the United States and China—a view that was strongly criticized at the time by South Korean conservatives and privately ridiculed by U.S. officials. Today, that approach looks even more naïve and dangerous than it did then.

Today, we live in a world where some Indo-Pacific nations are taking sides amidst escalating U.S.-PRC rivalry. China’s nuclear and conventional buildup, its threatening posture toward Taiwan and the Philippines, its expansive territorial claims in the East and South China seas, and tensions with Japan have led to regional pushback against China, including stronger alliance ties with Washington, more U.S. military deployments, and new regional partnerships of like-minded democracies (such as AUKUS and the Quad). The region appears to be girding itself for a protracted period of difficult relations with China, centered on intense U.S.-China competition.

It is widely expected that Donald Trump’s return to the White House will bring an even more aggressive posture toward China, particularly in the trade arena, and that this will lead to greater U.S. expectations of its regional allies, especially Korea.

Trump administration pressure on Seoul could come in the form of massive new defense burden-sharing demands, a shift in the mission of U.S. forces away from Korea and toward China and the Taiwan Strait, a reduction in U.S. troops in Korea, or all of the above. Faced with a U.S. president known for his anti-alliance views, disdain for Korea, and highly transactional nature, South Korea will be under enormous pressure to accommodate U.S. requests. South Korea’s continuing dependence on the United States for its security will make it hard to resist this pressure.

The above is likely to be the situation regardless of the outcome of the Korean Constitutional Court’s verdict on Yoon’s impeachment. But if, as is widely anticipated, Yoon is ultimately replaced by a president from the progressive DPK, a period of difficulty in U.S.-Republic of Korea (ROK) ties may ensue. The DPK has stridently criticized Yoon’s policies on North Korea, China, Russia, and Japan—already putting the party at odds with current U.S. positions. Beginning with differences over China, the potential for a range of serious differences with the Trump administration to arise could create a crisis in the alliance.

The long-standing approach of “economy with China, security with the United States,” is no longer applicable under the Yoon administration. While the Yoon administration has not pursued full decoupling from China, it has adopted a strategy of de-risking, focusing on trade and investment diversification in response to China’s economic coercion, while also aligning with U.S. efforts to restructure global supply chains. Since the deployment of a U.S. Terminal High Altitude Area Defense battery to South Korea in 2016, South Korea became aware that China was willing to weaponize asymmetric economic interdependence, to the detriment of major industries in South Korea. In 2021, a urea solution shortage crisis also made it clear that South Korea’s economy is vulnerable to disruption when its supply chains of raw materials are dependent on China.

In the security domain, the Yoon administration released an Indo-Pacific strategy within its broader foreign policy framework, aiming to position South Korea as a global pivotal state, albeit with half-hearted support from the opposition DPK. This strategy emphasized active engagement with the Indo-Pacific region and contributed to shaping a favorable balance of power for democratic like-minded countries. To this end, trilateral cooperation between South Korea, the United States, and Japan has been revitalized, serving as a crucial component within the networked security architecture in the region.

Even under a second Trump administration, it is anticipated that the emphasis on the Indo-Pacific will persist, particularly as long as the administration prioritizes outcompeting China. In such a scenario, the networked security architecture designed to enhance the U.S.-China competition—encompassing both the latticework of trilateral cooperation and resilient defense industry integration—will effectively serve its strategic purpose. Consequently, the trilateral partnership between South Korea, the United States, and Japan will likely continue to function as a key deterrent against North Korea, which remains a primary concern for South Korea. Just like during the first Trump administration, there is a possibility of suspending the U.S.-ROK military exercises to facilitate talks between the United States and the Democratic People’s Republic of Korea (DPRK), but the broader trilateral cooperation between South Korea, the United States, and Japan could serve as leverage to initiate talks with North Korea.

However, under a policy of retrenchment, the Trump administration would likely emphasize burden-sharing with U.S. allies and greater integration for collective defense. Given the administration’s focus on the U.S.-China rivalry, it is plausible that ROK-U.S.-Japan cooperation will be expected to extend beyond the Korean Peninsula, with an emphasis on strategic flexibility in security commitments. In this context, South Korean domestic public opinion is expected to be divided. Moreover, if South Korea holds an early presidential election after Yoon’s impeachment, there is a strong possibility that Seoul will be led by the progressive DPK, which has traditionally favored a hedging strategy between the United States and China, potentially reversing the Yoon administration’s foreign policy achievements. Seeking dialogue with North Korea and attempting to improve relations with countries like Russia and China to that end, the DPK could weaken South Korea’s commitment to the strategic clarity that the Yoon administration has proclaimed.

A second Trump administration will sharpen the choice for Seoul on its strategic alignment between Beijing and Washington. The Trump administration will play hardball in pressuring Seoul to move toward Washington in its overall strategic orientation, including by potentially threatening to limit security support and/or ratchet up trade tensions if Seoul fails to heed Washington’s requests. The Trump team is unlikely to accept the slogan, “economy with China, security with the United States.” For the Trump team, any South Korean support for China’s efforts to climb value chains is not just an economic concern but also a security threat. The Trump team views China’s bristling industrial capacity as a security threat, given the potential that Beijing could concentrate its production capacity to field military capabilities at a scale that Washington would struggle to match.

The Trump administration will not be as solicitous as the Biden administration was of South Korean involvement in Japan-Republic of Korea-United States activities. Under Trump, Washington will not give Seoul the benefit of the doubt or overlook issues of concern in deference to alliance solidarity and the trilateral coordination mechanism.

Rightly or wrongly, Trump prefers to deal directly with adversaries rather than invest the efforts required to build alliance cohesion for dealing with countries such as China. Trump is instinctually wary of making concessions in service of alliance unity. He also may see limited potential upside for such efforts given political disarray in Seoul and Japanese Prime Minister Shigeru Ishiba’s tenuous hold on power in Tokyo.

Ultimately, though, the key factor that will inform the trajectory and velocity of growth in the U.S.-South Korea alliance over the coming years may be the South Korean people’s decisions about their own governance. So long as Seoul is in political disarray, it will be hard to make progress on any major issues in the alliance. While the near-term outlook for the alliance is uncertain, I remain confident over the mid- and long-term. There is strong bipartisan public support for the alliance in South Korea and the United States. The U.S.-South Korea alliance has become less politicized in South Korea; support for the alliance extends across the spectrum from conservatives to progressives. While the tone and tenor of alliance management discussions could change depending on who succeeds Yoon, the alliance’s broad overall direction will remain positive. Both countries confront common threats. Both countries hold shared interests in preserving regional stability and conducive conditions for economic growth. Notwithstanding the near-term potential for political turbulence, these conditions create a strong foundation upon which the alliance can grow in the years ahead.

Designing South Korea’s foreign economic and security strategies is inherently complex as they form the two fundamental pillars of the country’s national security and economic growth. In the 2010s, South Korea pursued an economic partnership with China while simultaneously strengthening its security alliance with the United States. However, this dual-track strategy is no longer sustainable.

The United States seeks to militarily balance and check China and decouple economic and technological sectors that could contribute to Chinese military capabilities. Under the Biden administration, this has taken the form of “de-risking” and targeted decoupling in advanced technology fields. With the return of the Trump administration, there is a high likelihood of pursuing decoupling across all sectors, including trade.

China, on the other hand, outwardly supports a just and inclusive economic order but continues to engage in trade practices perceived as unfair and economic policies inconsistent with liberal norms. Preparing for potential economic decoupling with the United States, China has pursued a “dual circulation” economic strategy since 2020 that emphasizes prioritizing internal circulation (such as increasing domestic consumption and technological self-reliance), diversifying and globalizing supply chains, and attracting foreign investments. More significantly, China seeks to expand its influence through military assertiveness in the South China Sea and toward Taiwan while enhancing its deterrence posture over the “First Island Chain” and advancing regional connectivity with the Belt and Road Initiative.

These developments suggest that South Korea’s economic and security strategies can no longer remain separate. The securitization of economic policy is already underway with South Korea needing to account for potential economic retaliation from China due to geopolitical disagreements and to partially align with U.S. efforts to counter China economically. While debate continues over the scope of securitization, it is clear that economic and security matters will increasingly move toward an integrated framework. Moving forward, Seoul’s strategy will include maintaining a strategy of economic diversification, strengthening South Korea’s deterrence capabilities through the ROK-U.S. alliance, and enhancing its economic and security frameworks to adapt to an increasingly fragmented global order.

The economic relationship between South Korea and China has shifted from being mutually complementary to increasingly competitive, creating structural challenges for bilateral cooperation. This transformation is driven by China’s rapid technological development, industrial advancement, and the intensifying U.S.-China rivalry, which has forced South Korea to navigate a difficult strategy between its security alliance with the United States and its economic relations with China.

In particular, during the Trump era, South Korea must closely monitor U.S.-China dynamics and adjust its strategies accordingly. This involves mitigating potential economic fallout, expanding economic partnerships beyond South Korea’s dependence on China, and ensuring that South Korea’s security strategy bolsters deterrence capabilities in coordination with the United States and its allies. As a middle power, South Korea must tread carefully to maintain its long-term security and economic stability in a rapidly changing global landscape.

The new “comprehensive strategic partnership” between Pyongyang and Moscow is a major challenge for the U.S.-ROK alliance. If Moscow supplies Pyongyang with high-tech military assistance, this new partnership could alter the military balance on the Korean Peninsula and beyond.

It is unclear what Russia has promised to the DPRK in return for its support for Moscow’s war against Ukraine. But Russia could provide technologies that would greatly boost North Korean defenses and enhance its threat against South Korea, Japan, and the U.S. homeland. Such technologies might include upgraded air defense systems, modern fighter aircraft, cruise missile technology, assistance with nuclear warhead miniaturization and shielding, solid-fuel missile technology, and assistance with North Korea’s submarine-launched missile program.

Meanwhile, Moscow is already providing the DPRK with food, fuel, and hard currency, which help sustain Kim’s regime, and with diplomatic support in the United Nations Security Council, which shields Pyongyang from the effects of international sanctions.

The PRC, North Korea’s longtime treaty ally, is probably of two minds about the growing ties between Pyongyang and Moscow. On the one hand, Russia’s willingness to provide arms and technology to the DPRK could reduce China’s influence on Pyongyang and embolden the North Korean regime to act in provocative ways that could undermine China’s security.

But, at the same time, Beijing realizes that an enhanced North Korean threat against South Korea, Japan, and U.S. forces in the region would greatly complicate the security calculus of the United States and its regional allies.

However, Beijing’s sensitivity to growing Russian influence over its North Korean ally and concern about North Korean adventurism may offer an opportunity for the United States and South Korea. Indeed, Washington and Seoul may be able to leverage this to influence Chinese thinking about the danger of Moscow arming North Korea and convince the PRC to dissuade Russia from providing sensitive technologies to Pyongyang.

To take advantage of this opportunity, Washington and Seoul should respond to Russia’s provision of significant upgrades to Pyongyang’s conventional and nuclear capabilities by enhancing the U.S. military presence on and around the Korean Peninsula, strengthening ROK conventional capabilities (including strike capabilities) against key North Korean targets, and increasing the scope and tempo of U.S.-ROK military exercises, including trilateral exercises with Japan. The message to Beijing conveyed by these steps would be that China’s failure to stem Russian aid to Pyongyang is endangering China’s own security. In the end, China may decide that its geostrategic interests lie in supporting its Russian and North Korean partners. But there is reason to believe that a bold effort, supported by the use of quiet diplomatic channels, that reminds Beijing of the risk it is incurring, might give China second thoughts about the wisdom of leaning toward Moscow and Pyongyang.

North Korea-Russia strategic cooperation, which has led to the deployment of North Korean troops in the Ukraine war, the signing of a mutual defense treaty, and technological cooperation, is posing significant challenges for South Korea. North Korea is gaining operational experience from the Ukraine war and acquiring new military technologies. With the mutual defense treaty, Russian involvement in contingencies on the Korean Peninsula has become a more feasible scenario. It is also reported that Russia will transfer submarine technology, air defense technology, and reentry technology for intercontinental ballistic missiles to North Korea, which could certainly impact the Korean Peninsula’s military balance. As a result, discussions on strategic cooperation between South Korea and European countries appear increasingly inevitable. In addition to humanitarian support and reconstruction pledges for Ukraine, the Yoon government has also considered providing lethal weapons. Efforts are being made to counter North Korea’s troop deployments while further strengthening solidarity with European countries.

In the context of U.S.-China competition, North Korea’s provocations and alignment with Russia will undoubtedly place considerable pressure on China. Moreover, Seoul is focusing more on ROK-U.S. cooperation and trilateral cooperation between South Korea, the United States, and Japan, thereby enhancing its deterrence posture toward North Korea, which will certainly pose a security burden on China. In response to these geopolitical shifts, China has recently sent conciliatory gestures toward South Korea. This is not only due to the emergence of North Korea-Russia cooperation, but also because, for China, South Korea is a valuable trade partner as Beijing prioritizes economic recovery. Furthermore, the Trump administration has announced an additional 60% tariff on China, making South Korea an increasingly important partner for Chinese trade diversification. Finally, Beijing’s alignment with Seoul is likely to serve as a warning to North Korea, which continues its strategic cooperation with Russia.

This situation is likely to provide an opportunity for South Korea and the United States to weaken the North Korea-China-Russia alignment and maintain a stable relationship with China. However, the rapprochement between Seoul and Beijing is expected to have limits, as Seoul emphasizes strategic clarity and alignment with the United States, directly mentioning the peaceful resolution of the Taiwan issue and cooperating with the United States and Japan in this regard. If early presidential elections are held and the progressive DPK comes to power, the space for ROK-China cooperation may widen.

If handled deftly and subtly, North Korea’s deepening relationship with Russia should offer openings for South Korea and the United States with China. Here’s why: China’s strategic interests would be ill-served by a division of Northeast Asia into a northern triangle comprising China, North Korea, and Russia versus a southern triangle comprising Japan, South Korea, and the United States. If Northeast Asia were to split into a northern and southern bloc, China would face a heightened risk of ideologically-infused conflict along its periphery. Beijing would become further entangled with Russia and North Korea, thus cementing China into an inferior grouping of countries with a demonstrated record of insensitivity to China’s strategic considerations. Lastly, if such a scenario were to emerge, China would risk losing access to the South Korean and Japanese technology and capital upon which Beijing still relies for reaching its national development goals.

So long as Beijing believes it is possible to avoid the region’s division into rival blocs, it will work to avoid such an outcome. If, on the other hand, Beijing believes such a division into rival blocs is inevitable and unavoidable, then it will cut its losses with Seoul and Tokyo and move forward with Pyongyang and Moscow.

Here’s the rub, though. Beijing will not publicly disavow Pyongyang or Moscow. It will not allow any appearance of a wedge to emerge between itself and its northern partners. To the extent that Seoul or Washington pushes Beijing to publicly condemn North Korea’s support of Russia’s war aims in Ukraine, it will be effectively pushing Beijing toward Pyongyang and Moscow and undermining its own strategic interests in the process.

China is not a swing actor. In its hierarchy of strategic priorities, ensuring Russia does not fail in Ukraine and President Vladimir Putin does not fall is among Beijing’s highest objectives. President Xi Jinping has invested significant personal political capital into his relationship with Putin. Xi deeply believes that Russia provides a valuable backstop for China. In addition to offering strategic depth, the Sino-Russian relationship ensures China has sanctions-proof access to vital energy, food, and military resources. Thus, as much as China holds reservations about deepening North Korea-Russia relations, Beijing is unlikely to publicly condemn or disavow either country.

Rather than attempting to wrest Beijing away from deepening ties with North Korea and Russia, a good outcome for Seoul and Washington is keeping China invested in its relationship with South Korea (and Japan). This can be done through continuing trilateral leader-level summits between the PRC, ROK, and Japan; continuing sub-leader level exchanges between all three countries; and normal commercial relations between all three countries outside of trade in technologies with military applications. Continuing to keep China engaged and invested in developing its relations with South Korea and Japan is the best preventive diplomacy against the region’s cleaving into northern vs. southern triangles and all the uncertainty and risk such an outcome would entail.

Since North Korea’s failed negotiations with the United States at Hanoi in 2019, Pyongyang has reoriented its national strategy by combining self-reliance with a “new Cold War” strategy. North Korea aims to strengthen its military deterrence capabilities through its nuclear and missile programs while leveraging the evolving multipolar global environment to deepen cooperation with China and Russia. This strategy seeks to secure recognition as a nuclear-armed state and ensure economic survival. Concurrently, North Korea has rejected engagement with South Korea and the United States while actively seeking partners capable of supporting its economic needs and military advancement.

North Korea’s cooperation with Russia primarily focuses on enhancing its independent military deterrence capabilities by acquiring advanced military technologies, including nuclear-powered submarine capabilities, reentry technology for intercontinental ballistic missiles, and reconnaissance satellite systems.

However, uncertainties remain regarding Russia’s willingness to transfer high-end military technologies to North Korea. North Korea may also receive economic assistance from Russia, although the scope of assistance remains limited compared to China’s economic support. As a result, North Korea-Russia cooperation is likely to yield short-term, partial benefits rather than sustained, long-term gains for both countries.

Trump has pledged to bring an early end to the Ukraine war, a scenario that would weaken North Korea’s strategic leverage and strain its cooperation with Russia. Some may think that North Korea has greater motivation to hold a summit with the United States in this situation. However, North Korea is unlikely to seek a premature summit that could restrict its military technology development before fully acquiring nuclear missile capabilities capable of threatening the U.S. mainland. Therefore, it will be challenging for a U.S.-North Korea summit to achieve meaningful results in the short term.

While China has cooperated with Russia over the Ukraine war, it has stopped short of openly endorsing the conflict. Unlike Russia, which directly challenges the U.S.-led international order, China seeks to preserve the existing system while positioning itself as a future hegemonic power. China remains cautious about North Korea’s growing military capabilities, particularly as they could destabilize Northeast Asia. China fears that increased North Korean provocations would lead to stronger military cooperation among South Korea, the United States, and Japan—an undesirable outcome for Beijing. Consequently, China does not seem to welcome deepened North Korea-Russia military cooperation. However, it is unlikely that China will implement specific policies to limit military cooperation between North Korea and Russia. Based on past patterns, China has shown a tendency to refrain from active intervention as long as North Korea does not significantly undermine China’s geopolitical interests. Should the Ukraine war end and North Korea recognize the limitations of its reliance on Russia, Pyongyang could seek to restore and strengthen its relationship with Beijing.

Similarly, trilateral cooperation among North Korea, China, and Russia remains inherently limited. Current relations are a combination of bilateral alignments rather than a fully formalized trilateral framework. Although North Korea, China, and Russia continue to coordinate and balance their interests, an official summit or structured triangular alliance has yet to materialize. Moving forward, their relationships will be defined by cycles of conflict, coordination, and recalibration, maintaining a fragile and pragmatic triangular cooperation.