South Korea-US Relations: The Moon Years

Despite the modern push for simplicity in analysis, presidential legacies are complex. This is no less true of the soon-to-be-departing Moon Jae-in administration. Moon’s domestic policies will matter most for South Koreans, but for many outside South Korea the evaluation will be on his handling of South Korea-U.S. relations and North Korea.

Those relationships, however, were also increasingly complex during the Moon administration. The United States was shifting from being a proponent of free trade to a more protectionist posture that would directly affect South Korea’s trade with the United States. The Trump presidency presented Moon with the prospect of war on the Korean Peninsula for the first time since 1953, but also a unique opportunity to achieve significant progress in addressing the nuclear issue with North Korea.

Moon was able to take advantage of some of these challenges, but ultimately had to navigate his country through a time of increasing turbulence in South Korea-U.S. relations and an escalation in North Korea’s ballistic missile and nuclear weapons development.

Holding South Korea-U.S. Relations Together During the Trump Years

The most significant challenges to South Korea-U.S. relations, as with other U.S. allies in recent years, came from the Trump administration. With an “America First” philosophy and a belief that U.S. allies had been taking advantage of the United States the Trump administration almost immediately began pushing for changes in the economic relationship with South Korea once Moon was elected.

After their first summit in 2017, new U.S. President Donald Trump – who had previously called the Korea-U.S. free trade agreement (KORUS FTA) a “horrible deal” and a job killer – announced that a newer, fairer trade agreement would be negotiated. This had not been discussed in the summit with Moon and was the first sign of the economic tensions that would develop in the relationship.

Trump, seemingly intent on withdrawing from the KORUS FTA, ultimately pushed South Korea to renegotiate the agreement. Despite the fanfare of the Trump administration on its victory, the Moon administration was able to limit the revisions to a few minor areas related to automotive trade, pharmaceuticals, and a few other issues. However, the agreement to extend the phase-out of the U.S. light truck tariff for 20 years likely pushed back any plans by Hyundai and Kia to export light trucks to the United States in the near future.

The KORUS FTA was not the only economic test that the Moon administration had to navigate. The Trump administration initiated Section 232 national security investigations into imports of steel and automobiles. While the automotive case was ultimately dropped, the steel case pushed South Korea to negotiate a quota limiting its exports to the United States. Initially, this benefited South Korea as its products could still enter the U.S. without facing the new Section 232 tariffs, but as the Biden administration has begun removing those tariffs the quota has placed South Korea at a disadvantage.

Relations on national security were no less challenging. The Trump administration initially favored a policy of maximum pressure to bring North Korean leader Kim Jong Un “to his senses,” as then-Admiral Harry Harris put it. This was in contrast to the Moon administration’s preference for engagement. With Trump promising “fire and fury” to stop North Korea’s nuclear weapons and ballistic missile tests, Moon utilized North Korea’s outreach during the 2018 PyeongChang Olympics to move Trump toward diplomacy and lessen the prospect of war on the Korean Peninsula.

The move to bring Trump and Kim together initially appeared to be a success for Moon. Kim voluntarily pledged to suspend tests of nuclear weapons and ballistic missiles. Trump agreed to a summit meeting with Kim and became the first sitting U.S. president to meet with the leader of North Korea at a summit in Singapore, signaling a potential shift in the relationship.

The two sides reached an initial agreement in Singapore. While light on details, the agreement set out to improve North Korea-U.S. relations and build a lasting peace on the Korean Peninsula, and reaffirmed North Korea’s commitment “to work towards complete denuclearization of the Korean Peninsula.” To the surprise of everyone, Trump also announced the end of major South Korea-U.S. military exercises, having not informed Seoul in advance of the decision.

Expectations were high that a follow-up summit in Hanoi in 2019 would result in an agreement between the United States and North Korea that would lift some sanctions in exchange for a partial dismantlement of North Korea’s nuclear weapons and ballistic missile programs. It was not to be. Trump ultimately left Hanoi early unsatisfied with Kim’s dismantlement offer. While Trump and Kim would meet briefly in the DMZ four months later, talks between the United States and North Korea were effectively dead despite Moon’s continued efforts to bring the two sides together.

While Trump and Moon would eventually come to see eye-to-eye on dialogue with North Korea, Trump held fast on his conviction that South Korea was not paying enough under the two countries’ military burden sharing agreement. The Trump administration initially demanded South Korea pay $5 billion – a 400 percent increase – in talks for a new Special Measures Agreement (SMA), but the Moon administration refused. While Washington eventually brought its ask down to a 25 percent increase, the agreement was ultimately allowed to lapse and not renewed during the Trump administration.   

Despite the frictions at times over North Korea policy and the SMA with the Trump administration, Moon was able to negotiate a revision of the missile guidelines that constrained Seoul’s own development of ballistic missiles to allow for the development of space launch vehicles.

Repairing South Korea-U.S. Relations During the Biden Years

After the turbulent years of the Trump administration, Moon found a partner in new U.S. President Joe Biden who was looking to repair relations with U.S. allies. However, the Biden administration gave Moon little traction for restarting a dialogue between the United States and North Korea.

Shortly after Biden’s inauguration, the United States and South Korea reached an agreement on a new SMA. The new agreement will run through 2025 and includes an initial 13.9 increase in Seoul’s contribution. The agreement also includes future increases to mirror changes in South Korea’s defense spending.   

Moon also quickly built on the progress made with the Trump administration on revising the bilateral missile guidelines to negotiate their removal with the Biden administration.

The initial summit between Biden and Moon also refocused the relationship, with the United States and South Korea committing to work together to address the pandemic, climate change, supply chain vulnerabilities, and new technology.

However, Moon’s efforts to restore dialogue between the United States and North Korea prior to the end of his time in office have been unsuccessful. Moon negotiated language for a potential end of war declaration with the United States, but Pyongyang ultimately showed little interest in talks to formally end the Korean War.

While Moon has not made the progress on North Korea he wanted, he successfully navigated the tensions during the Trump administration. In doing so, he was able to minimize the potential damage from Trump’s efforts to end and later renegotiate the KORUS FTA, though his administration’s quota agreement on steel over time has come to look less successful. He also avoided a break in the alliance over the SMA, while ultimately keeping increases in South Korea’s burden sharing contribution to a reasonable amount. With the agreement for deeper cooperation on climate change, supply chains, technology, and the pandemic, he has strengthened the relationship and left it in a better place than it was five years ago.