In the aftermath of South Korean President Moon Jae In’s successful meeting with North Korean leader Kim Jong Un on April 27th, the signing of a formal peace treaty to end the Korean War and bring an end to over 70 years of hostilities between the two powers appears imminent. With President Moon having briefly crossed the border into the north for the first time, lead by hand by Marshall Kim at Panmunjom, the symbolic demarcation line between the two countries, Moon proceeded to lead his northern counterpart into the south for a banquet, a symbolic tree planting and the signing of highly symbolic accords. It represented the first official visit by a North Korean head of state to the south, with South Korean law having previously strictly forbidden any such visits. An end to the armistice and signing of a formal inter Korean peace treaty is set to have significant implications, not just for the two powers, but also for the United States which has stationed troops in South Korea since the territory was passed to the jurisdiction U.S. military government by the surrendering Japanese Empire in 1945.
With U.S. forces deployed to South Korean under the pretext of protecting the country from the north should the armistice be broken, the signing of a peace treaty could well lead to their withdrawal from the Korean Peninsula. While the U.S. military currently stations almost 30,000 troops in South Korea, this contingent pales in comparison to the size of the forces deployed during the Cold War at the behest of both Seoul and Pyongyang. With Korea bordering both the Soviet Union (today Russia) and China, its strategic importance cannot be overstated, and in the aftermath of the Korean War the United States deployed hundreds of thousands of troops to South Korea, which remained there for several decades. Following the unilateral U.S. withdrawal from article 13D of the armistice agreement, the military also deployed tactical nuclear weapons to the country, which alongside deployments in Taiwan and Okinawa were a formidable asset aimed not only at Pyongyang, but also at Beijing and Moscow. While South Korea is strategically valuable, it is not as essential to the U.S. military’s position in the Pacific today as it once was - indeed, the garrison there could well be seen more as a liability than an asset given its small size and close proximity to Chinese and North Korean assets which give it a high likelihood of being stranded and cut off from the remainder of the military in the event of war.
U.S. Defence Secretary Jim Mattis stated during a meeting at the Pentagon regarding the possible withdrawal of troops from the Korean Peninsula on the day of the Moon-Kim summit: "Well, that's part of the issues that we'll be discussing in the negotiations with our allies first and, of course, with North Korea.” The withdrawal of U.S. troops has long been called for by South Korean activists in light of a number of the high number crimes committed involving American personnel in Korea, from drug trafficking to rape and manslaughter, as well as environmental dangers stemming from the deployment of military equipment near populated areas and the perception that such deployments make South Korea a target in the event of a regional war involving the U.S. While the loss of South Korea as a staging area for military operations would hinder the U.S. position in East Asia, it is hardly the greatest loss that Washington could face in the region should an inter Korean treaty be signed. The United States has long maintained another critical asset in South Korea, one which could well prove decisive in the event of a regional conflict, which is wartime command of the South Korean military.
While U.S. troops deployed to East Asia number less than 100,000, South Korea retains one of the largest and most powerful military forces in the world which in wartime would field close to 4 million men. The military is renowned for its high levels of training, maintains a high defence budget of almost $50 billion annually, and deploys some of the world’s most sophisticated weapons systems from Sejong the Great Class destroyers to K2 Black Panther battle tanks, K9 Thunder Artillery Pieces and F-15K strike fighters. Indeed, South Korea's armed forces may well be among the top five most capable and advanced in the world, ranking behind only the U.S., Russia, China and India, and combines scale and modernity in a way few others can match. The United States currently retains wartime operational command over the South Korean military, meaning that should war break out in the region the U.S. would be in full command of one of the largest armed forces in the world - and could theoretically order a joint offensive against Chinese targets, a full scale invasion of North Korea or any other action which would suit U.S. interests in the Pacific. The value of this asset cannot be overstated, and could well be key to success in any war effort waged in the region and do much to minimise the United States military's own losses.
While the U.S. military’s withdrawal from South Korea in the aftermath of an inter Korean peace agreement would represent a considerable loss for Washington, the loss of command over South Korea’s armed forces would be a far more serious setback - particularly in light of the growing strategic importance of the Asia-Pacific region. President Moon Jae In has made a number of calls rescind this wartime operational control and return South Korean sovereignty over its armed forces, stating in a speech at an Armed Forces Day ceremony on September 28 2017: "retrieving wartime operational control will boost military development and place South Korea at the centre of East Asian security, based on independent defence capabilities." Ultimately the United States will struggle to compensate for the loss of what is arguably its most capable wartime asset in the region, and is likely to firmly oppose a return of wartime operation control to Seoul. Peace between the two Koreas may well seriously undermine U.S. efforts to maintain a favourable balance of power in East Asia as a result.