The Constitutional Court’s decision on impeached President Yoon Suk Yeol this week comes on the heels of 18 weeks of political turmoil in South Korea that has ground the government to a halt. While the decision closes one chapter, it opens another one of bitter polarization and political infighting. The biggest casualty of this unprecedented domestic crisis, however, may be happening across the Pacific. The confluence of months-long political stasis in Seoul and the start of the second Trump administration has precipitated a quiet crisis in the U.S.-Korea alliance that neither side will admit to.
Defense Secretary Pete Hegseth’s first trip to reaffirm U.S. defense commitments with Indo-Pacific allies last week noticeably skipped South Korea. The apparent reason was that it made no sense to meet with his counterpart or the acting president, both of whom would not be in office in a couple of months. This bypassing of the key U.S. ally takes place at a time when Donald Trump talks openly about meeting again with Kim Jong-un and refers casually to the North Korean leader as “a nuclear power,” suggesting that the United States has given up on denuclearization. Indeed, like he has done with Russian President Vladimir Putin and Ukrainian President Volodymyr Zelensky, Trump displays a tendency to negotiate with adversaries first and then present a fait accompli deal to allies. By contrast, Trump has shown no interest in talking with the interim head of state in the South, which is understandable given that any agreement reached with the acting government in Seoul wouldn’t be worth its weight in paper given the impeachment crisis at home.
Trump’s breakneck pace of rolling out new policies comes at a time when South Korea cannot respond to any of them. Following the 25 percent tariffs on steel and aluminum, which took effect on March 12, the total value of South Korea’s steel exports in March declined by 10.6 percent year-on-year. The 25 percent tariffs on the Mexico automotive sector are expected to cause a Korean automative export decline of 7–13 percent. The 25 percent tariffs on all foreign cars and the 25 percent reciprocal tariffs on all Korean exports to the United States only adds to the burden. In his Joint Address to Congress, Trump singled out South Korea as having an average tariff rate “four times higher” than those of the United States (which was technically incorrect, as the free trade agreement between the United States and Korea effectively sets the average tariff rate at 0.79 percent). But South Korea’s $66 billion trade surplus puts the country in Trump’s crosshairs of “unfair” trading partners. While other world leaders like Justin Trudeau, Claudia Sheinbaum, Shigeru Ishiba, Narendra Modi, Emmanuel Macron, and Keir Starmer have made initial visits with Trump to kiss the ring and to cut deals for tariff exemptions, the impeachment crisis has left South Korea leaderless to do the same. Bureaucrats and business leaders have come to D.C. to try to fill the void, albeit unsuccessfully.
Meanwhile, Trump continues to plow ahead with more policies likely to have major impact on Korea. As the Pentagon under Hegseth moves to realign military force postures in the Indo-Pacific to better counter the threat from China, Korea may see changes to the U.S. troop deployments on the peninsula, as well as demands that Seoul accept that the revised force presence be “strategically flexible” to move off the peninsula in case of a Taiwan fight—something Koreans have long resisted for fear of being entrapped in a U.S.-China war. During his first term, the president also made hay over South Korea’s failure to sufficiently contribute to the costs of the U.S. presence in Korea, and he is likely to throw away Biden’s five-year burden-sharing deal (ending in 2030) and try to squeeze additional billions more annually from the ally.
Trump is moving at 100 miles per hour while the leaderless South Koreans are stuck in neutral. Even a relatively minor issue like the Department of Energy’s listing of South Korea on the “Sensitive and Other Designated Countries List (SCL)” proved to be a major embarrassment for the rudderless alliance. Both sides were completely caught off guard by the decision, which was made late in the Biden administration when neither side was paying attention. And the absence of a leader in South Korea to request a call with Trump to resolve this quickly allows the issue to fester.
The only foreign policy issue in South Korea, meanwhile, that is gaining momentum is one that is not in U.S. interests—that is, the growing calls for going nuclear. The combination of North Korea’s unchecked nuclear buildup and uncertainty about Trump’s commitment to South Korea’s defense has led to a groundswell of calls for South Korea’s nuclearization. According to recent polls, 66 percent of South Koreans support their country going nuclear. Prominent Korean political leaders in both the conservative and progressive camps have not ruled out such policies, with some openly supporting them.
South Korea enters the next phase of its political crisis this week, but by the time the crisis is resolved and a leader is in place, the damage to the alliance may be beyond repair.
Victor Cha is president of the Geopolitics and Foreign Policy Department and Korea Chair at the Center for Strategic and International Studies (CSIS) in Washington, D.C.
