The Peninsula

Between Beijing and Washington: South Korea’s Alliance Dilemma in the Trump-Lee Era

Late last month, South Korean President Lee Jae Myung met President Donald Trump in the White House in what was arguably Lee’s most difficult foreign policy test to date. If the goal was to avert another Oval Office spectacle between Trump and a world leader, win over Washington’s policy elite, and avoid further demands from Trump on tariffs and alliance burden-sharing, Lee passed with flying colors. The smiling photo of Trump and Lee in the Oval Office and Trump’s unusually positive depiction of South Korea with the press spoke volumes about Lee’s pragmatism and political instincts.

However, by focusing on issues where the two leaders were likely to find synergy and alignment, such as Korean peace, issues central to the U.S.-South Korea security relationship were left unaddressed. In fact, many in Washington and Seoul anticipated that the summit would offer further clarity on issues such as strategic flexibility—that is, the use of U.S. Forces Korea (USFK) in contingencies outside of the Korean Peninsula (e.g., a Taiwan Strait conflict) and the Lee administration’s approach to U.S.-China relations. Neither of these issues was mentioned at the White House (although Lee did respond to a question about China during a Q&A with CSIS President John Hamre).

Understandably, Lee may not have wanted to raise politically sensitive issues with Trump in public to ensure a smooth bilateral meeting. However, the shift from the era between presidents Joe Biden and Yoon Suk Yeol of “values-based diplomacy” to the pragmatic and transactional foreign policy approach adopted by Trump and Lee, respectively, may require some degree of alliance calibration. Although working-level discussions have been ongoing, at some point, Trump and Lee will have to weigh in on issues that will ultimately define the direction of the U.S.-South Korea alliance and their approach to China.

To start, the Trump administration is asking Asian allies to contribute more to their defense and collectively step up military coordination to deter China. Although Trump did not raise the issue in his meeting with Lee, Trump officials will continue to press South Korea to push its defense spending upwards to at least 3.5 percent, if not the five percent NATO benchmark. The Trump administration is also banking on allies like South Korea to align their security goals with the United States’ broader mission in the Indo-Pacific. For Lee, that may mean offering more commitment and credibility behind strategic flexibility that goes beyond the loose statement drafted between Secretary of State Condoleezza Rice and Minister of Foreign Affairs Ban Ki-moon in 2006. Or it could mean taking on greater responsibility for the defense of the Korean Peninsula in the event of a Taiwan conflict—a scenario Under Secretary of Defense for Policy Elbridge Colby had argued prior to joining the second Trump administration.

Greater clarity on strategic flexibility—especially if it encompasses Taiwan—would be a problem for Lee, who wants to maintain positive relations with China. The commitment would have to be given in private or left in general terms without specifying any country or conflict scenario.

In contrast, Lee may welcome the idea of increasing South Korea’s defense spending and taking on greater responsibility for the defense of the Korean Peninsula, especially if it enables Lee’s progressive Democratic Party to fulfill a longstanding goal of regaining wartime operational control (OPCON) over its own military. But there is a catch. If a division of labor is created with USFK oriented toward regional conflict and South Korean forces taking greater responsibility for defense and (conventional) deterrence on the peninsula, concerns regarding alliance credibility and alliance abandonment may emerge in Seoul. Will the United States defend South Korea against North Korea, or will it prioritize deterring China? Or worse yet, could Trump use the division of labor or Lee’s desire for OPCON transfer to justify a significant drawdown of the 28,500 U.S. troops stationed in South Korea?

For now, the Trump administration has stated North Korea as the primary focus of the alliance and broader regional threats (read China) as “shared priorities.” But that prioritization may be subject to change depending on how rising geopolitical competition unfolds.

 

Andrew Yeo is Senior Fellow and SK-Korea Foundation Chair at the Brookings Institution.

Photo from The White House.

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