Quincy Brief

The U.S.-South Korea Alliance: Toward a Relationship of Equals


  • Donald Trump’s extreme demands on South Korea are counterproductive to his stated objective of reducing the security cost of the U.S.-South Korea alliance to the United States.
  • Instead of weakening relations with South Korea, the United States should focus on salvaging diplomatic talks with North Korea. Only through a peaceful resolution to the longstanding conflict between the Koreas can the existing terms of the U.S.–South Korea security relationship be revised.
  • The U.S. foreign policy establishment’s view of South Korea is antiquated and perpetuates a de facto protectorate relationship with Seoul. Ultimately a security-independent South Korea would better serve U.S. interests.


President Trump contends that “very rich and wealthy countries” like the Republic of Korea should pay more for American troops stationed in their countries. While a more balanced burden-sharing arrangement is necessary, the U.S.’s demand for a five-fold increase in South Korea’s contribution, from $924 million to $5 billion, threatens to tear apart the bilateral relationship and undermines U.S. interests on the Korean Peninsula. The issue demanding attention is not who pays how much, but whether the existing terms of the U.S.–ROK security relationship remain pertinent or must be revised.

The long-term goal of U.S. grand strategy should be to facilitate the creation of a peaceful global order consisting of fully sovereign, law-abiding states capable of providing for their own security. Any state that hosts foreign forces and relies on those forces for its defense is not fully sovereign: It is dependent upon others to ensure its security. This describes the Republic of Korea today.

During the first decades of South Korea’s existence, this dependence—centered on the U.S.–ROK military alliance—was necessary and made sense. Today, a reevaluation of the bilateral military relationship is in order.

It is in the United States’ long-term interest for countries like South Korea that have relied upon American security to manage their own affairs, without external security assistance. A perpetual stationing of U.S. troops on the Korean Peninsula serves the interests of neither Washington nor Seoul. Rather than undermining the South Korean president by pushing for an unrealistic increase in burden-sharing, the United States should recognize that a strong and independent South Korea will ultimately reduce U.S. military costs on the Korean Peninsula and pave the way for an eventual troop withdrawal. Unnecessarily antagonizing South Korea at a time of high-stakes talks with North Korea will weaken our democratic ally at a time when we need it to serve as a genuine partner rather than a quasi-client.

A paradigm shift is needed in U.S.–ROK relations, one that envisions a collaborative reorientation towards a more independent South Korea that is less reliant on American security. Trump’s approach, on the other hand, appears to be aimed at increasing South Korean psychological insecurity only to charge it a higher price to protect it, thereby perpetuating a de facto protectorate relationship.

History of U.S. Military Involvement on the Korean Peninsula

There is little understanding in Washington of the U.S.–South Korea alliance apart from the fact that our two nations fought side-by-side two generations ago. Open debate about the merit of having a U.S. military presence in the Korean peninsula has traditionally been a virtual taboo, though that has changed with President Trump. To appreciate how the Special Measures Agreement defining the terms of the two nations’ burden-sharing fits within the broader U.S.–ROK relationship, we must first grasp what the U.S. military presence in Korea has been from its inception and how it developed into a deeply unequal relationship between the world’s largest and twelfth-largest economies.

The United States and South Korea exist in radically different circumstances. Whereas the United States has a population of more than three hundred million people and is flanked by friendly neighbors, Canada and Mexico, South Korea is a small country of fifty million people surrounded by three major powers: China, Russia, and its former colonial ruler, Japan. It also borders the Democratic People’s Republic of Korea, which invaded South Korea in 1950 and has repeatedly attacked South Korea over the past seven decades, including the attack on Yeonpyeong Island in 2010 — an incident that killed four South Koreans and injured 19. To this day, the Korean War is technically ongoing, so the two Koreas live in a state of war separated by the most fortified demilitarized zone in the world.

In contrast, the United States is relatively safe, strong, and secure. It spends more on defense than the next seven most expensively armed countries combined. It does not suffer from a strategic sense of vulnerability, as South Koreans do. Whereas the U.S.’s connection to the Korean War is a distant memory, the trauma of war is a living part of South Koreans’ everyday experience.

The history of the U.S. military presence in South Korea sheds useful light on South Korea’s long pursuit of security with regard to its much more powerful neighbors, while at the same time it has sought to be a “normal nation” that can shape its own destiny.

Whereas the U.S.’s connection to the Korean War is a distant memory, the trauma of war is a living part of South Koreans’ everyday experience.


In 1882, the United States and Korea established diplomatic relations by way of a pact called the Treaty of Peace, Amity, Commerce and Navigation. This treaty has sometimes been misrepresented in Korean as the “Chosun–U.S. Protection [italics added] and Commerce Treaty,” denoting a sense of mutual defense. In fact, the treaty was a standard text for the United States when establishing relations with other countries during that time period, and it did not imply an alliance.

Some American missionaries and political representatives who entered Korea after Washington established diplomatic ties may have encouraged Korean hopes for U.S. support against aggressors. The United States used inspiring rhetoric about democracy and freedom, but its leaders preferred to focus on commerce rather than military entanglements. During the Japanese colonial period, 1910 to 1945, Korean intellectuals took to heart President Woodrow Wilson’s Fourteen Points speech, delivered at the Paris Peace Conference in 1918, in which he emphasized democracy and the national right to self-determination. This idea eventually inspired the Koreans’ peaceful uprising of the March 1, 1919 Independence Movement against the Japanese empire. Japan’s brutal suppression of the Korean people’s appeal, and Korea’s appeal to the international community—including the United States—were both ignored. This painful history resulted in an ideological divide that remains evident in South Korean politics today: Progressives turned to Marxism as an alternative to western ideology, while anti-communist, conservative leaders such as Syngman Rhee, a long-serving political figure and South Korea’s first president, looked to the United States as a beacon of light in its pursuit of freedom and democracy.


The end of World War II marked the demise of Japan’s empire and a freed Korea. But U.S. military involvement in Korea proved to be highly controversial, as a backdoor agreement with the Soviet Union, reached with no input from the Korean people, divided the Korean Peninsula along the 38th Parallel. This was never intended to be a permanent arrangement; it was understood, rather, as a short-term solution until the Korean Peninsula could be stabilized.

The years 1945 to 1950 marked a period of strategic ambiguity when it came to U.S.–South Korea relations. Some analysts have blamed Dean Acheson, President Truman’s secretary of state, for excluding Korea from the American defense perimeter in his January 12, 1950 speech at the National Press Club. Given that Acheson mentioned Japan, Okinawa, and the Philippines in his remarks—and omitted South Korea and Taiwan—the North Koreans read the speech as a diplomatic green light to invade the South. Others do not place blame squarely on Acheson for precipitating North Korea’s invasion five months after he spoke, arguing that there were more prominent domestic factors that led to the civil war. Whatever the case, war broke out in June 1950. President Truman immediately sent troops to South Korea.

The Korean War marked a turning point in U.S.–ROK relations, transforming a strategically insignificant bilateral relationship into an alliance forged in blood. The Korean War lasted from 1950 to 1953, with massive casualties on all sides. Historians estimate that between three million and four million people were killed. It is estimated that as many as 70 percent of the dead may have been civilians. Two months after the United States, North Korea, and China signed an armistice that halted hostilities, the United States and South Korea signed a Mutual Defense Treaty codifying that if either side is attacked by a third country, the other party will come to its defense.

The death of the two girls brought out pent-up grievances about the U.S. military, such as its excessive use of land, rapes, and environmental damage.


The Korean War has had myriad complex effects on South Koreans. In general, there is gratitude and a sense of affinity toward the United States for its pivotal role in fighting North Korea. South Korean conservatives have over time interpreted this sentiment to mean that the United States’ protection is indispensable to South Korea’s security and its identity as a democracy.

At the same time, South Korean progressives, particularly those of the younger generation, have grown concerned over the years that U.S. forces may never leave Korea, regardless of the Korean people’s will or capabilities to defend themselves. High-profile incidents at or near U.S. bases have further sharpened this divide. In 2002, for example, a U.S. Army vehicle struck and killed two middle school students, Hyosun Sin and Mison Sim, at Yangju Highway in Gyeonggi-do, South Korea. An uproar ensued, with massive candlelit vigils and calls for a revision of the Status of Forces Agreement to give the Korean government legal authority to handle such cases. The death of the two girls brought out pent-up grievances about the U.S. military, such as its excessive use of land, rapes, and environmental damage.

Among the most problematic legacies of U.S. military presence in South Korea has been violence against women. In her 1997 book, Sex Among Allies, Katharine Moon shows how the U.S. and ROK governments not only tolerated prostitution near U.S. bases but coordinated efforts to maintain it. When President Richard Nixon announced in 1969 that the U.S. may reduce the number of American troops in South Korea, Korean women were effectively used as a tool to discourage troops from leaving. Such violent and destabilizing aspects of the U.S. troop presence are often ignored by those who posit that Washington’s engagement in East Asia always has been a decidedly benign force.

Providing for the transfer of operational control of Korean troops from the United States to South Korea in the event of war, a concept called OPCON transfer, is an important element of an eventual U.S. withdrawal from the Korean Peninsula. But because the Republic of Korea has depended on the United States for its military operations for so long, how and when OPCON transfer should take place remains unclear. On the one hand, many South Koreans see this step as vital to South Korea’s sovereignty and autonomy. On the other hand, there is growing concern that making such a move without denuclearization of the Peninsula could leave South Korea vulnerable to the nuclear-armed North. Ultimately, it is in the U.S.’s interest to create the conditions necessary for South Korea to eventually defend itself.

Current Debate on U.S.–ROK Cost-Sharing Agreement

Asia has become more prominent in discussions of U.S. foreign policy, commerce, and national security under the Trump administration. Policymakers seem anxious about how to deal with a rising China and fears about Beijing’s long-term aims in the region. Might a reduced U.S. military presence encourage what many understand to be China’s imperial ambitions to carve out a sphere of influence in East Asia? Will North Korea attack South Korea absent a substantial U.S. presence in the South? Will a revision of the U.S.–ROK military relationship signal the end of American preeminence in the Pacific?

Coupled with this uncertainty about the U.S.’s place in Asia are concerns about America’s long-term strategic interests in the region. Ever since his presidential campaign, President Trump has repeatedly argued that the United States cannot continue to finance troops overseas without more cost-sharing by its European and Asian allies. In May 2016, MSNBC reported that candidate Trump had this to say about cost-sharing with South Korea and Japan:

“They’re paying us a tiny fraction of what it’s costing. I’d love to continue to defend Japan, I’d love to continue to defend South Korea – we have 28,000 soldiers on the line between North and South Korea right now. It’s costing us a fortune, which we don’t have, we’re a debtor nation. I’d like them to pay up. They have a lot of money, both of those nations, we take in Japan’s cars by the millions.”

According to Brown University’s Cost of War Project, the federal government has spent or appropriated $5.9 trillion dollars on the wars in Afghanistan, Pakistan, and Iraq through the 2019 fiscal year, which ended September 30. The notion of ending “endless war” permeates this year’s presidential debates; advocacy groups are increasingly vocal in making the case that a smaller defense budget can mean more money toward domestic jobs and programs. Democratic presidential candidates such as Tulsi Gabbard and Pete Buttigieg are calling for foreign policies that reduce U.S. military footprint abroad.

At a time when the American public is rightly weary of paying for American troops to police the world, policymakers must be open to alternatives to an indefinite U.S. military presence in East Asia. Indeed, President Trump’s demand for South Korea to pay more for U.S. troops illuminates three challenges to the U.S.–ROK relationship:

1. The U.S. establishment’s view of South Korea is antiquated.

Underlying the debate on the Special Measures Agreement with South Korea is the fact that the U.S. foreign policy establishment has long viewed itself as an indispensable power on the Korean Peninsula, regardless of how much South Korea develops or what the South Korean people want. This view is not only obsolete; it no longer aligns with U.S. strategic interests in the region.

For too long, the foreign policy establishment has made it difficult for American taxpayers to understand why we spend such considerable sums of money on defense, and whether doing so brings about peace that allows for our troops to come home. The federal government’s annual budget process is spread across multiple committees and bills, and are separately considered, even if they all contribute to the broad national security goals. We do not have regular public debates on the number of U.S. troops stationed in East Asia or the types of armed forces we need to counter twenty-first century threats, nor do we hold policy makers accountable for the effectiveness (or otherwise) of their strategies.

It is easy to think that our long-term strategy on the Korean Peninsula is contingent upon peace that only the U.S. military can assure. As General Vincent Brooks, former commander of U.S. Forces in Korea, recently stated, “The DNA of [South Korea’s] military is our DNA…. [Their] thriving democracy is also our DNA. But our work is not finished… because the country is not at peace. Until there is peace, prosperity, security, stability… our work is not done.” Such statements imply that the United States is the arbiter of whether or not South Korea has peace, while downplaying South Korea’s right as a sovereign nation to decide its own future.

2. A security-independent South Korea lies in the U.S.’s strategic interest.

The American foreign policy establishment tends to treat the question of U.S. goals on the Korean Peninsula as a foregone conclusion, as opposed to a strategic matter that warrants continuous debate. Even raising the possibility of a reduced military presence, or of signing a peace agreement to formally end the Korean War, is commonly met with dismissal. For example, Sue Mi Terry of the Center for Strategic and International Studies stated in a recent podcast interview that “serious Korea scholars… don’t even need to debate why we have troops in South Korea and why it’s so important.”12 Such disdain for debate ignores the reality that American taxpayers want to know whether or not our defense spending actually advances their national security interests. Parents who send their sons and daughters to the demilitarized zone should have reasonable confidence that their presence is essential and makes conflict less likely. Simply saying that the United States can never leave Korea is wrong; it is also a disservice to the U.S.’s 200,000-strong volunteer force that is overtaxed by repeated overseas deployments and suffering from various well-publicized pathologies afflicting members of the armed forces.

Most important, it is in the United States’ strategic interest that prosperous countries such as South Korea—a country that has transformed itself from an international aid recipient to an aid donor in 60 years—become security independent. Washington should welcome the prospect of an ally whose security no longer falls on the shoulders of the United States. It made sense for the United States to be the principal partner in the post–World War II relationship, when Korea was freed from Japanese colonialism but suffered the ravages of the Korean War, but times have changed. Further, studies show that lengthy military occupation can elicit nationalist sentiment and open resentment. Demanding an unreasonable increase in our cost-sharing agreement harms long-term U.S. interests. Weakening Washington’s relationship with Seoul makes South Korea less secure and creates a greater burden for Americans to shoulder in the long run.

3. The U.S. and South Korea need to be united to counter North Korea.

Key to eventually withdrawing U.S. forces from the Korean peninsula will be the reduction of tensions between the two Koreas as achieved through intensive diplomacy. Negotiations on burden-sharing between the United States and South Korea may be a necessity and something most Americans would welcome, but they are ultimately of secondary importance. In this regard, the Trump administration’s shock-and-awe approach on this question is counterproductive and may lead to greater tensions on the Peninsula at a volatile time. If the United States is serious about reducing military costs in East Asia—with approximately 78,500 military personnel currently stationed in South Korea and Japan—we must reach a diplomatic solution to North Korea’s nuclear challenge in close partnership with Seoul.

President Moon Jae-in has been deeply invested in diplomacy with North Korea, whether at the Pyeongchang Winter Olympics or at the 2018 inter–Korea summit, where the two Koreas agreed to work toward the complete denuclearization of the Korean Peninsula Moon has often served as an intermediary between Washington and Pyongyang, encouraging both sides to stay the course in negotiations. For instance, it was after U.S. Vice–President Mike Pence met with President Moon at the Pyeongchang Winter Olympics that Pence announced that the United States would be willing to talk to Kim Jong Un without preconditions.

Mishandling bilateral relations with South Korea could significantly weaken President Moon’s ability to pursue talks with North Korea, which in turn would make it more difficult for the United States to bring the troops home and reduce the cost to U.S. taxpayers. Any sign of capitulating to the United States would diminish support for Moon’s agenda and weaken the bilateral relationship. Ultimately, absent President Moon and his dedicated efforts, talks with North Korea may fail, potentially dragging us into war.


When the U.N. Command signed the armistice in 1953, it was intended to be a temporary agreement until a stable peace emerged on the Korean Peninsula. Nearly 70 years later, it is time to talk about what the U.S. presence on the Peninsula should look like and how peace can actually be achieved through the creative use of diplomacy. A myopic focus on burden-sharing risks weakening South Korea during crucial talks with the North while dividing Washington and Seoul, much to Pyongyang’s advantage. This, in turn, risks increasing the cost of the U.S. presence in the Peninsula by fueling tensions there.

President Trump is right to point out that the cost of keeping American troops in South Korea is unacceptably high. How he is handling the issue, however, is likely to make it more—not less—expensive for American taxpayers.

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