South Korea’s left-leaning administration is developing close ties with communist China, raising national security concerns for its relations with the U.S, the chairman of the House Select Committee on China warned in a letter.
“Recent developments in the Republic of Korea’s (ROK) economic, technological, and diplomatic posture toward the People’s Republic of China (PRC) pose significant risks for the United States,” Rep. John Moolenaar stated in a letter to Secretary of State Marco Rubio.
The South Korean administration of President Lee Jae Myung has developed close economic and political ties with China since Mr. Lee took office in June 2025.
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The American alliance with Seoul remains critical, and thus a “structural shift” by South Korea toward Beijing requires close monitoring and action, the chairman stated in a five-page letter sent Monday.
The letter quoted Mr. Rubio from recent House testimony saying South Korea’s elected leaders are “taking positions that run contrary to the national interests of the United States.”
Disclosure of the letter comes as President Trump announced on social media Wednesday that he met Mr. Lee in New York and the two leaders agreed to $200 billion in new U.S. investments.
The House Armed Services Committee also voiced its concerns over the national security dangers of increasing South Korean-Chinese alignment.
That committee’s fiscal 2027 defense authorization bill contains a provision requiring the Pentagon to conduct an assessment of Chinese Communist Party malign influence in South Korea and the risks to U.S. defense interests.
Actions by South Korea related to China include nine months of high-level leader engagement, deepening semiconductor investment in China, and discriminatory treatment of American companies compared to Chinese competitors, the Michigan Republican stated in the letter.
South Korea has concluded 14 memorandums of understanding on increasing trade, science and technology, digital ties, intellectual property relations and quarantine standards, the letter stated.
Mr. Moolenaar said he is especially concerned by Chinese President Xi Jinping’s invocation of “shared” Chinese and Korean sacrifices against Japanese militarism. The references are a clear attempt to drive a wedge between two key regional treaty allies, South Korea and Japan, at a time of deteriorating relations between Beijing and Tokyo over Taiwan, he said.
China’s closer engagement with South Korea also is part of an expanding communication on export controls and supply chains, the letter says.
Such channels are setting up a parallel system to allied export control coordination that allows the Chinese into ally policy deliberations while “China’s critical mineral export controls are tantamount to an ’economic declaration of war against the United States,’” the letter stated.
China also is being positioned to coerce supply chains in South Korea as large companies remain deeply invested in manufacturing in China, the letter said.
Samsung Semiconductor operates electronic memory plants in Xian and Dalian, and SK Hynix makes computer chips in Wuxi.
The facilities “pose serious points of [Chinese Communist Party] leverage against allied global supply chains,” Mr. Moolenaar said.
The pro-China policies are compounded by what the letter said is biased enforcement of South Korean law against U.S. companies in favor of Chinese firms.
Chinese e-commerce platforms are being used by 16.5 million South Koreans monthly, including through a subsidiary of Alibaba, that has been labeled a Chinese military company by the Pentagon.
South Korean authorities have documented theft of personal data and sale overseas but little action has been taken by the Seoul government, the letter said.
By contrast, the American company Coupang in South Korea has faced large-scale legal harassment by authorities, including over 400 facility raids, more than 4,400 document requests, and ultimately imposing $409 million in penalties.
“This widening gulf is especially concerning in light of the 2026 National Defense Strategy’s assessment that the ROK is capable of assuming primary responsibility for deterring North Korea and reorientation of U.S. Forces Korea (USFK) toward broader regional contingencies,” Mr. Moolenaar said. “Even more concerning is Seoul’s posture toward regional contingencies.”
A recent U.S.-China warplane incident over the Yellow Sea prompted criticism of U.S. Forces Korea operations but not the Chinese military conduct, he said.
In February, some ten U.S. F-16 fighter jets from Osan Air Base in South Korea engaged in a brief, non-combat mid-air standoff with scrambled Chinese military fighters over international waters in the Yellow Sea.
Mr. Moolenaar also said Seoul has effectively ruled out support for joining U.S. and regional militaries in responding to any conflict over Taiwan.
The position was stated by Mr. Lee, who was quoted in the letter as saying: “[W]hat does it matter to us what happens in the Taiwan Strait?”
The chairman also criticized the disclosure of classified U.S. information in March by South Korean Unification Minister Chung Dong-young.
The leak of intelligence on North Korea led to restrictions on intelligence sharing with Seoul.
While the U.S.-South Korea alliance remains indispensable, South Korea’s shift away from important U.S. national security interests is not something to take lightly, he said.
Mr. Moolenaar said the select committee is working to combat Chinese threats and attempts to undermine the posture of the U.S. and its allies. As a result, panel wants the State Department to provide a briefing by Oct. 31 on South Korea-China ties and the administration’s response.
A spokesman for the State Department declined to comment. The South Korean Embassy did not immediately respond to a request for comment.
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