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US-Korea Military Alliance

By Daniel Oh

Though the character of US-Korean relations has evolved over its one-hundred thirty year history, the US-ROK Military alliance has served as the foundation to the relationship since its existence.

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For over sixty years, the United States-Republic of Korea (ROK) military alliance has served as a stabilizing force in a region where the interests of four great powers intersect on a peninsula roughly the size of Idaho. Even today, senior US government officials hail the alliance as a lynchpin of regional security in Northeast Asia.

Though the origins of the alliance stem from the Korean War, it has displayed remarkable longevity as the two nations navigated the height and conclusion of the Cold War, responded to an evolving threat from the Democratic People’s Republic of Korea (DPRK), and adapted to the security environment of the Twenty-first century.

The U.S-ROK Mutual Defense Treaty signed on October 1, 1953, serves as the backbone of the military alliance. The treaty was not, however, unique to the ROK as the US signed similar agreements with Japan, Thailand, the Philippines, Australia, and New Zealand beforehand. What makes the US-ROK Mutual Defense Treaty truly unique is not its existence, but rather that as a sovereign country, the ROK voluntarily placed control of its military in the hands of a foreign entity, an arrangement that still exists to a certain degree today.

The modern South Korean military has yet to experience a day where American forces did not actively contribute to the ROK’s defense. Though the character of US-Korean relations has evolved over its one-hundred thirty year history, the US-ROK Military alliance has served as the foundation to the relationship since its existence.

US-ROK Mutual Defense Treaty

While significant levels of American involvement in Korea did not occur until 1945 following Japan’s surrender of World War II, the origin of US-Korean relations lies in 1882 with the Joseon-US Treaty of Peace, Commerce, and Navigation. This treaty, signed on the deck of the USS. Ticonderoga on May 22, 1882, was the Joseon Dynasty’s first treaty with a Western nation. As other world powers increasingly encroached on its interests, the Joseon Dynasty hoped that the US would serve as a force for arbitration and aid (see The History of the ROK-US Alliance: 1953-2013, Seoul: Institute of Military History, 2014, 24). Unfortunately, US interest in Korean affairs proved to be short lived as the Taft-Katsura Agreement signed in 1905 essentially traded Japanese domination over Joseon for American supremacy in the Philippines (The History of the ROK-US Alliance: 1953-2013, 25). Forty-five years later, the US made an unquestionable commitment to Korea following the invasion of North Korean forces into the South on June 25th, 1950. After three years of fighting resulting in an estimated 142,901 casualties to include 33,629 American servicemen killed in action, the US and ROK forged what is still known today as a “Blood Alliance” (see James P. Finley, The U.S. Experience in Korea, 1871-1982: In the Vanguard of ROK-US Relations, San Francisco: USFK, 150).

Despite the recognition of mutual sacrifice during the war, the Allies did not see eye to eye when determining how to end it. President Dwight D. Eisenhower entered office in 1953 after running on a platform that called for ending a Korean War that had reached a stalemate. One of his top priorities once in office was to establish an agreement that would essentially end combat operations in Korea. The People’s Republic of China (PRC) and the DPRK also expressed willingness to explore the possibility of a cease-fire agreement. Eisenhower’s objective, however, ran directly counter to that of Syngman Rhee, the South Korean President. Rhee openly opposed a cease-fire and actively called for continued operations until the Peninsula had been forcefully unified. Central to Rhee’s plan was ensuring that the US, as the leader of all United Nations (UN) forces fighting in the war, would remain at the ROK’s side should it push north. Rhee believed that the mechanism that would bind the US to the ROK was a Mutual Defense Treaty.

Rhee was an ardent anti-communist who believed that the ROK could serve as a stalwart partner to the US as it waged the Cold War. In Rhee’s mind, the Mutual Defense Treaty would not only ensure the ROK’s security, but could also serve as one cog in a broader Pacific Alliance that included the Philippines, Thailand, and Taiwan. Anti-communism and the US would be the binding forces of this broad alliance (The History of the ROK-US Alliance: 1953-2013, 60). Unfortunately, Eisenhower’s early views on a US-ROK Mutual Defense Treaty differed greatly from Rhee’s. Eisenhower initially displayed reluctance to enter into an arrangement that would involuntary commit the US to renewed combat against the DPRK. As a nation with a volatile political situation and unstable government, the ROK did not immediately inspire confidence as a necessary treaty partner. Eisenhower also expressed concerns that any Mutual Defense Treaty between the US and the ROK would undermine the existing UN efforts on the peninsula and weaken the UN’s mandate. Eisenhower would gradually warm to the idea of a US-ROK security pact that could be part of a Pacific-wide collective security system in the spirit of NATO, something that Rhee had advocated since he took office in 1948.

The US-ROK Mutual Defense Treaty did not come to fruition as a result of orderly discussions and agreements, but was rather used as a negotiating chip. Despite Rhee’s open hostility against a cease-fire, the US successfully came to terms with the PRC and DPRK on an Armistice agreement that would end the war in 1953. As a means to disrupt this agreement, Rhee ordered the release of anti-communist North Korean POWs on June 18, 1953, the same day that North Korean, Chinese, and UN forces planned on signing the Armistice. In response, the US offered Rhee treaty negotiations if he agreed to no longer disturb cease-fire negotiations. The US, PRC, and DPRK effectively ended the Korean War after signing a military Armistice Agreement on July 27th, 1953. The US Secretary of State, John Foster Dulles, arrived in Seoul less than two weeks later to conduct Mutual Defense Treaty talks. The US and the ROK signed the pact on October 1st, 1953 which for over sixty years, has succeeded in its meeting its original purpose of preventing another Korean War.

The US Military Commitment to the ROK

While the Mutual Defense Treaty is the foundation of the Military alliance, the presence of a Combined U.S-ROK military force in the ROK serves as the Alliance’s clearest manifestation. Even today, a permanent American military presence remains in the ROK with an American General Officer serving as the wartime commander of all military forces in the country. The origin of American command over Korean military forces, more commonly referred to as operational control (OPCON), extends back to the early days of the Korean War when President Rhee transferred authority to General Douglas MacArthur, the Commander of UN Forces. As a follow-up to the Mutual Defense Treaty, the November 17th, 1954 Agreed Minutes solidified this command relationship while both documents served as the basis for a permanent US military presence in the ROK. This agreement placed the South Korean military under the operational control of the UN Command headed by an American General. The Minutes also specified the UN Command’s responsibility in defending the ROK and committed the US to robust economic and military assistance. US economic assistance to the ROK from 1953-1961 totaled an estimated $2.3B, or roughly eight percent of the country’s Gross National Product during the period. Military assistance during the same period neared $1.4B, more than thirty percent of the total military assistance provided by the US to East Asia and the Pacific. Though the ROK no longer receives any type of aid as an affluent G-20 country today, it still remains the only nation that places the command of its forces under the US military in its own country.

As the UN’s role in the country diminished and the ROK military grew in size and capability, the relationship between the US and ROK forces also changed. US military leadership realized early on that integrating the ROK military into planning and execution functions would only increase the overall effectiveness of the Combined Force. A Combined operational planning staff created in 1968 further developed into an integrated field army headquarters in 1971. A significant milestone in military cooperation occurred in October 1978 when both countries agreed to establish the Combined Forced Command (CFC), a defense structure that allowed unified military operations. The agreement called for a four-star American General Officer serving as the CFC Commander with a four-star Korean General Officer as the Deputy Commander. Each of the command’s staff sections would also have both ROK and US military representation. The CFC’s establishment in 1978 symbolized a lasting commitment by the US to the ROK’s defense in spite of the noticeable numerical decrease of American military forces on the peninsula over the years.

The perception exists that the US-ROK Alliance has been asymmetric for many decades with some referring to the relationship as a Patron-Client arrangement. ROK dependence on the US for security, however, has gradually declined over the years as ROK military capabilities continued to advance, supported largely by unprecedented economic growth from the 1980s. Rather than a Patron-Client construct, the U.S and the ROK are now partners that maintain mutual goals and shared beliefs. The ROK’s assumption of peacetime operational control of its military forces in 1994 represented a significant achievement in this partnership. Though an American military officer still maintains command in wartime, both governments agreed in 2007 to chart a path towards the ROK also gaining wartime operational control, a situation where US military forces in the country would be subordinate to ROK command during war. The 1953 Mutual Defense treaty still provides the groundwork for military cooperation today, while the U.S-ROK Military alliance underpins a relationship between two Allies that continues to grow in scope.

Recommended Readings

The History of the ROK-US Alliance: 1953-2013. Seoul: Institute for Military History, 2014.

Curtis, Gerald L. and Sung-joo Han, eds. The US-South Korean Alliance: Evolving Patterns in Security Relations. Lexington: Lexington Books, 1983.

Finley, James P. The US Military Experience in Korea, 1871-1982: In the Vanguard of ROK-US Relations. San Francisco: USFK, 1983.

Kwan, Tae-hwan, ed. US Korean Relations 1882-1982. Seoul: Kyungnam University Press, 1982.

Paik, Seung-gi. US-Korean Security Relations since 1945. Seoul: Seoul Press, 1990.

Shin, Gi-Wook. One Alliance, Two Lenses: US-Korea Relations in a New Era. Stanford: StanfordUniversity Press, 2010.