South Korea’s domestic tumult risks being exploited by China

Beijing will see the removal of South Korea’s president and subsequent election as an opportunity to undermine Seoul’s alliances, at a time of rising tensions with the US.

Expert comment Published 11 April 2025 4 minute READ

Dr Edward Howell

Korea Foundation Fellow, Asia-Pacific Programme

One week ago, South Korea’s constitutional court voted to remove the country’s now-former President Yoon Suk Yeol, following his initial impeachment by the national assembly on 14 December 2024. Preparations are now underway for the snap election of a new president, which will be held on 3 June.

Amidst ongoing political division in South Korea, Yoon’s dismissal will have serious consequences for Seoul’s foreign policy, especially at a time of heightened competition between Washington and Beijing. South Korea’s politics is increasingly polarized, and China will wish to exploit this division to undermine a crucial US alliance.

South Korea’s next steps

Yoon is the third South Korean president to be impeached – following Roh Moo-hyun and Park Geun-hye in 2004 and 2016 respectively – and the second to be removed from office by the country’s constitutional court. His battles are just beginning, as he continues to face criminal charges – separate to his impeachment – pertaining to ‘inciting insurrection’.

Yoon maintains significant domestic support. In the weeks following his December impeachment, as opposition parties called for his arrest, his approval ratings notably soared, reaching just over 50 per cent in early February. At the same time, protests have continued in support of and against the now-former president.

Last week’s verdict has now set in motion a nearly two-month campaigning period before the general election. The main political parties will look to hold primaries later this month.

Democratic processes have been – and are being – followed in South Korea. That said, Yoon’s sudden and surprising declaration of martial law on 3 December 2024 – the first such occurrence in democratic South Korea – has adversely affected the country’s international reputation and contributed to the intensifying political polarization at home.

Continuity and change in South Korea

Yoon’s removal from power occurs at a precarious juncture in global politics. Thus far, the second administration of US President Donald Trump has adopted a transactional approach to diplomacy, which raises questions about the US’s commitment to South Korea and the durability of Seoul’s bilateral and trilateral ties with Tokyo and Washington.

Yoon’s…foreign policy significantly bolstered ties between Seoul, Tokyo, and Washington. 

Yoon’s unfinished presidential term was mired in scandal, not least involving his wife, Kim Keon-hee. Nevertheless, his foreign policy significantly bolstered ties between Seoul, Tokyo, and Washington. The trilateral summit at Camp David in August 2023 was a notable achievement for multilateralism, with all three states committing to strengthen relations in the face of common threats from the Indo-Pacific region.

Only months before the summit, Yoon signed the Washington Declaration with former US President Joe Biden, agreeing to increase US-South Korean defence cooperation, including a new Nuclear Consultative Group. The group aimed to manage the nuclear threats from North Korea through enhanced coordination and consultation on nuclear and strategic planning.

With Yoon’s removal, however, not one of the leaders who attended the Camp David Summit remains in power. Moreover, the Trump administration’s somewhat unpredictable foreign policy renders South Korea’s future relations with its regional and global allies and partners increasingly uncertain. 

During his 2024 election campaign, Trump called for Seoul to pay more for the deployment of US troops in the country. 

Whilst any withdrawal of these forces looks unlikely, assumptions about the US’s regional security architecture in East Asia are being challenged.

China’s exploitation of South Korea’s domestic politics

The US is unlikely to abandon its South Korean ally completely. Yet these changes to South Korea’s domestic and global environment will not go unnoticed in China. Beijing will likely seek to exploit the situation to its advantage.

On 30 March, the finance ministers of China, Japan, and South Korea met for their first dialogue in five years. The three countries agreed to hold ‘comprehensive and high-level’ talks with respect to a possible free trade agreement, although rumours that they would consider a joint response to US tariffs were quickly refuted by the South Korean government.

Tariffs pose a significant threat to South Korean businesses, particularly its automobile industry.

Japan, South Korea, and China were all surprised by the scale of the reciprocal tariff regime which the US president announced on 2 April, only days after the trilateral meeting took place. Tariffs pose a significant threat to South Korean businesses, particularly its automobile industry: in 2024 alone, South Korea’s automobile exports to the US amounted to a far-from-paltry total of nearly $35 billion, accounting for 42 per cent of Seoul’s total exports to the US.  

Trump subsequently ‘paused’ the imposition of these heightened tariffs on Japan, South Korea, and other countries, and instead maintained a flat 10 per cent tariff on all imports to the US, whilst escalating tariffs on China.

An additional tariff of 34 per cent was imposed on Chinese exports to the United States on 2 April, further to the 20 per cent imposed earlier this year. Beijing’s response was unsurprising, placing its own reciprocal tariffs of 34 per cent on US imports and restrictions on the export of rare earth elements.

Beijing is likely to leverage its economic brawn as it hopes to fray Seoul’s alliance with Washington and heighten its regional influence.

In light of Beijing’s assertion that it would ‘continue [fighting] to the end’, the Trump administration increased the tariff rate on Chinese imports to an astonishing total of 125 per cent. Beijing retaliated by imposing a further 84 per cent tariff on US imports.

For all Beijing’s alleged desire to cooperate with Tokyo and Seoul, China is no benign actor. At a time of political uncertainty in South Korea, and with its heightening tariff dispute with the US, Beijing is likely to leverage its economic brawn as it hopes to fray Seoul’s alliance with Washington and heighten its regional influence.

To that end, China would likely prefer a victory by the leftist Democratic Party. The Party’s likely candidate, Lee Jae-myung, has previously criticized the country’s US military presence. Prior to the 2022 election, he notably sympathized with China’s dissatisfaction at plans to deploy additional missiles as part of the US’s Terminal High-Altitude Aerial Defence system, stationed on the Korean Peninsula.

Having announced his intention to run for president earlier this week, Lee expressed his support for the ‘very important’ relations between Seoul, Tokyo, and Washington. However, actions speak louder than words.

Should the Trump administration’s tariff threats continue throughout the election campaign, Lee may choose to tone down any such pro-US rhetoric and instead revive his claims of the benefits of a South Korean economic tilt towards China.

Yet, recent speculation suggests that the Trump administration may prioritize deterring China over strengthening relationships with Europe. Any South Korean tilt towards an increasingly aggressive China risks placing Seoul’s foreign policy firmly at odds with that of its principal ally.

South Korea’s domestic politics therefore looks set to intertwine increasingly with global great power politics. Any new president will face extraordinary challenges, not least the increasing uncertainty of Washington’s foreign policy, Beijing’s ongoing desire to undermine South Korea’s alliances with the West, and domestic division at home. The outcome will be no insignificant moment.