South Korea’s alliance with the United States is facing growing strains amid disputes over investment, intelligence sharing, and diplomatic coordination, raising concerns about Seoul’s capacity to effectively respond to North Korea’s escalating nuclear activities.
In a rare public acknowledgment, South Korea’s ambassador to Washington, Kang Kyung-wha, told lawmakers that there are limitations in communication with the White House regarding intelligence sharing. Kang described the situation as “somewhat frustrating,” highlighting underlying tensions that have developed between the two allies. Earlier this year, reports emerged that a South Korean official had leaked classified U.S. intelligence about a covert North Korean nuclear facility, a claim that South Korean President Lee Jae Myung dismissed as “absurd.”
Complicating the relationship further, a prominent South Korean politician recently cancelled a planned visit to the United States due to a delayed visa, an incident that underscores the diplomatic friction. The Trump administration has also reduced the scale of joint military exercises with South Korea, and South Korea's National Intelligence Service was reportedly excluded from a trilateral meeting on North Korea involving the U.S. and Japan in Washington, allegedly at the U.S. request.
These developments follow months of tension over South Korea’s handling of investment agreements and accusations from Washington that Seoul has delayed approvals and discriminated against U.S.-listed companies such as Coupang. The disputes are now affecting the security partnership at a critical juncture as North Korea intensifies missile tests, and President Donald Trump signals a possible resumption of talks with North Korean leader Kim Jong-un.
Experts warn that deteriorating intelligence cooperation could undermine the foundation of the U.S.-South Korea military alliance. Victor Cha, chair of Korea studies at the Centre for Strategic and International Studies, described the situation as “serious” because it calls into question U.S. trust in South Korea as a reliable ally. Although there is currently no indication that the United States will reduce its troop presence—approximately 28,000 personnel remain stationed on the Korean Peninsula—limited intelligence sharing hampers Seoul’s ability to monitor and respond effectively to North Korea’s expanding nuclear capabilities.
Amid the disagreements, U.S. threats of imposing new trade penalties have gained additional prominence. A spokesperson from South Korea’s presidential office said the government is actively working to restore trust with the United States and reaffirmed that the alliance remains a central pillar of Seoul’s foreign and security policy. The National Intelligence Service did not provide comment when contacted.
A U.S. State Department official emphasized that Washington expects South Korea to meet the standards of a durable alliance, which has been a key element of regional security in the Indo-Pacific for over seven decades, particularly regarding intelligence and counterintelligence cooperation.