APEC Summit tests Korea’s regional diplomacy

South Korea’s real diplomatic challenge at the Gyeongju APEC summit begins with the U.S., China, and Japan at the table. U.S. President Donald Trump pressed South Korea on trade tariffs until the last minute, Chinese President Xi Jinping visits South Korea for the first time in 11 years, and Japan’s hardline Prime Minister Sanae Takaichi presents a firm stance. After five months in office, the Lee Jae-myung administration still faces uncertainty in its relations with Washington, Beijing, and Tokyo.

South Korea-U.S. trade talks have stalled, leaving the broader alliance uncertain. South Korea-China ties are caught between Seoul’s declaration that the era of favoring Washington is over and Beijing’s demand that Seoul not side with Washington. South Korea-Japan relations face a crossroads over whether to uphold past agreements and focus on future-oriented cooperation. The success of APEC diplomacy will hinge on resolving this uncertainty.

The first challenge is the South Korea-U.S. summit. If Seoul cannot meet U.S. investment expectations, postponing an agreement may be wiser. There is concern, however, that talks on strengthening deterrence against North Korea, a core alliance pillar, could be sidelined. Without U.S. extended deterrence, countering North Korea’s nuclear threats is difficult. Since the government took office, Seoul and Washington have not fully focused on the issue, and no extended deterrence commitment was made at the August summit.

U.S. policy toward North Korea remains ambiguous. It is unclear whether Trump would accept a nuclear freeze without full denuclearization or what his broader North Korea strategy involves. South Korea and the United States reportedly agreed to expand Seoul’s uranium enrichment authority, but officials must prevent domestic calls for nuclear armament during future talks on revising the nuclear cooperation agreement. If Washington tolerates Pyongyang’s nuclear program while hesitating on extended deterrence, it could encourage unnecessary nuclear ambitions in South Korea. The summit must reaffirm close coordination on denuclearization and deterrence.

Relations with China, strained by the 2016 THAAD retaliation, have seen little active diplomacy under recent administrations. Reviving dialogue will be a priority in a meeting with Xi Jinping, and resolving the decade-long informal ban on Korean pop culture is also necessary.

South Korea must balance its U.S. alliance while avoiding conflict with China. Success will depend on finding common ground between Washington’s China policy and Beijing’s demand that Seoul not join U.S. containment efforts. Although U.S.-China tariff tensions have eased, competition in technology and security is irreversible. Seoul must protect collaboration with U.S. firms in critical industries and make clear that Chinese construction in the West Sea threatens maritime sovereignty. Failing to set these boundaries could leave South Korea caught between Washington and Beijing.

If South Korea-U.S. ties are unstable, wavering relations with Japan would further erode South Korea’s diplomatic support. In meetings with Takaichi, Seoul should present South Korea-Japan cooperation as a stabilizing force for security and economic ties. Japan’s dialogue with North Korea on abductions provides a potential area for collaboration with Seoul. There is also potential for collaboration in advanced technology supply chains, including semiconductors, if historical disputes do not impede progress.

APEC provides an opportunity to boost national prestige, but a series of meetings with the U.S., China, and Japan presents major challenges. The summit could shape South Korea’s foreign policy for the next five years, and it remains to be seen whether the Yoon administration can establish a strong diplomatic foundation.