Since the end of World War II, the United States has been the most powerful country in the world. It took the lead in setting up the current rules-based international order, and its power further strengthened in the wake of the collapse of the Soviet Union. Despite the new era of great power competition with China, the United States’ global influence is still unmatched, even if the gap has narrowed considerably.
South Korea, one of the key allies of the U.S. in East Asia, has pinned its own security to the power and influence of the United States since the 1950-53 Korean War. Enhancing the level of bilateral relations between the two countries has been the top priority for every South Korean president. This unwavering focus is reflected in the economic sphere as well. As of 2024, the U.S. is nearly on par with China as South Korea’s top export destination, accounting for 18.7 percent of total exports, just shy of China’s 19.5 percent.
Given how U.S. President Donald Trump has treated South Korea since he returned to the White House, however, South Koreans now believe that the U.S. may not be on their side.
In late July, two days before the deadline set by Trump to impose a 25 percent levy on all goods imported from South Korea, Seoul and Washington reached a deal to decrease the tariff rate to 15 percent. Seoul was under pressure to reach a deal with the U.S., as the European Union and Japan had already succeeded in lowering the levy.
Yet despite Trump and South Korean President Lee Jae-myung’s confirmation of the deal, months later the two countries seemed to have been still negotiating over a key part of the deal – Seoul’s investment of $350 billion in the United States. According to an interview with foreign press ahead of his visit to New York last week, Lee said that he would be impeached should he accept the deal offered by the Trump administration.
Washington is reportedly demanding that South Korea hand over the $350 billion to the U.S. “in cash.” South Korean leaders have rejected this out of hand as unrealistic. Lee said the South would face another financial crisis like the one suffered in 1997 should it accept Trump’s demand.
It is understandable for the the Trump administration to demand that South Korea make investments to revive some devastated sectors of the U.S. economy such as ship building, considering the sacrifice of the U.S. troops made during the Korean War and its economic assistance to South Korea for the past decades, which was one of the main backgrounds for the South’s rapid economic development. However, Trump’s consistent demands for Lee to accept this unrealistic deal has clearly engendered anti-U.S. sentiment. Many South Koreans believe the U.S. is now extorting South Korea, not trying to reach a reasonable agreement.
Trump’s reckless behavior hasn’t helped. Hours before having a summit meeting with Lee on August 25, the U.S. president posted on Truth Social, saying “What is happening in South Korea? It looks like a purge or revolution.” His post bolstered the baseless accusations of far-right extremists in South Korea who believe that Yoon Suk-yeol, the impeached president, was the victim of political persecution. The far-right narrative claims, without evidence, that the South’s elections in the 2020s were rigged by the intervention of China – which brings up with their claims that Yoon’s illegal declaration of martial law, the cause of his impeachment, was justified. The Constitutional Court disagreed, and unanimously removed Yoon from office on April 4.
Some experts dismissed Trump’s harmful post as a strategy to create leverage ahead of the first meeting with Lee. However, he clearly overlooked the fact that his careless behavior toward Lee and South Korea has stoked anti-Trump and anti-U.S. sentiment among South Koreans.
When media reported over 300 South Korean workers had been detained by the U.S. Immigration and Customs Enforcement this month, South Koreans questioned how that could even be possible considering the so-called “ironclad” alliance between South Korea and the United States. The workers had been helping establish a $7-plus billion South Korean battery plant in Georgia – the same sort of investment Trump has been demanding.
Through all these actions, the Trump administration clearly demonstrated that South Korea is no longer a valued U.S. ally but only a foreign state that Washington seeks to extract money from – as much as possible.
The increasing economic pressure, highlighted by the soaring tariff burden and disproportionate investment demands, makes one thing clear: South Korea must actively dismantle its reliance on the U.S. market. The strategic shift must center on aggressive market diversification. Seoul needs to pivot its focus toward high-growth regions like Southeast Asia and India, while simultaneously deepening trilateral economic cooperation with East Asian neighbors such as China and Japan. Furthermore, Seoul must prioritize securing trade access across the globe, including expanding penetration into the European market. Assuming that Trump would continue demanding South Korea to make more investments in the U.S., South Korea’s economic stability now depends on its ability to forge robust and self-sustaining trade relationships independent of Washington’s capricious policies.
Lastly, the anti-U.S. sentiment stemming from Trump’s transactional diplomacy has profound implications for South Korea’s security posture. Trump has repeatedly demanded that South Korea pay more for the stationing of the 28,500 U.S. troops in South Korea, including its annual budget for defense. His reckless behavior and consistent demands for increased defense contributions have created a crisis of confidence that the U.S. might not protect South Korea if North Korea threatens to launch an intercontinental ballistic missile toward the mainland of the U.S.
For many South Koreans, this fear has reignited a critical domestic debate: self-reliance in the face of nuclear threat. With North Korea already possessing nuclear weapons, the priority for a growing segment of South Koreans is shifting from relying on the U.S. extended deterrence to securing an independent nuclear capability.
Regardless of Lee’s hope to construct peace on the Korean Peninsula without seeking to develop nuclear weapons, Seoul may face unbearable demands from the public over nuclear development unless Washington’s gesture toward Seoul remains truly “ironclad.”