Sojeong Lee’s research while affiliated with University of Tennessee at Knoxville and other places

In this study, we examine South Korea's foreign policy strategy in the context of the increasing strategic rivalry between the United States and China. We ask why South Korea is relatively hesitant to actively balance against China, especially compared to other US allies like Japan. We present a theory that examines how the lack of territorial and maritime disputes between a US ally and China affects an ally's foreign policy strategy in the US–China rivalry, to explain the case of South Korea. In general, when a US ally is engaged in an ongoing, active territorial and/or maritime dispute with China, we expect the US ally to more actively help the US balance against China. Because bilateral relations between the US ally and China are already tense, the US ally can afford to side with the US without being as vulnerable to Chinese retaliation. On the other hand, when a US ally has no ongoing, active territorial and/or maritime dispute with China, the US ally is expected to be more cautious in siding with the US against China because doing so can provoke China to retaliate in ways more costly than if they already had ongoing disputes. We find that without ongoing, active disputes with China, South Korea is more vulnerable to retaliation by China through critical issues like North Korea and trade. As a result, it is difficult for South Korea to side with the US in actively balancing against China.

South Korean President Yoon Suk-yeol has made strengthening the alliance relationship with the United States a key part of his foreign policy positions. At the same time, South Korea continues to maintain a decent relationship with China, pursuing a precarious position to decide its role in the context of the growing US–China rivalry. The US has made the trilateral cooperation and close coordination among the US, South Korea, and Japan the centerpiece of its Indo-Pacific strategy, while South Korea and Japan have maintained their contentious relationship. The articles in this special issue address the challenges that South Korea faces today, focusing on two major themes in the contemporary era: first, how the US–China rivalry and power competition affect South Korea’s security and economic foreign policies, and second, how the bilateral tensions between South Korea and Japan affect regional security and alliance capabilities.

South Korea and Japan have maintained tense bilateral relations over their unresolved historical and territorial disputes for decades. The US has repeatedly called for improved relations between South Korea and Japan and underlined the importance of US–South Korea–Japan trilateral relations to address North Korean threats and regional security challenges. Would we, then, expect the US to play a role in helping to mediate South Korea–Japan problems? If so, under what conditions and to what extent would the US get involved in South Korea–Japan disputes? If not, what makes the US hesitate to do so? We argue that US involvement in South Korea–Japan bilateral relations depends on the degree to which the US perceives the tensions as costly and risky for US national security interests. With an issues-based analysis, a granular examination of South Korea–Japan trade disputes and the spat over the GSOMIA in 2019, and qualitative interviews with former US government and military officials, we find that the US is more likely to involve itself in South Korea–Japan relations and more likely to use its leverage as a major power with its allies when it perceives significant risks to its capabilities to address security challenges, primarily those posed by North Korea.

Since the end of World War II, the US military has continuously deployed troops to South Korea. The alliance works as an asymmetrical alliance, where the US is a patron and South Korea is a protégé. While it is argued that this deployment has significant political, economic, and military effects on South Korea and the region, few studies have examined how the presence of US forces there enhances US military and economic power as well as national security interests. In this paper, we examine the costs and benefits of the US–South Korea alliance, specifically focusing on US troop deployment on the Korean Peninsula. In particular, we argue that the US military alliance with South Korea has significant benefits to both partners, but particularly for the sake of US national security interests. In this sense, the protégé state provides significant benefits to the patron state. We discuss the strategic importance of South Korea in US foreign policy in the region and emphasize the benefits of the US–South Korea alliance at the various levels.