Thomas Jefferson believed firmly in avoiding unnecessary entanglements in the affairs of other nations. He also had a distrust of standing armies and believed government spending on defense had to be kept within reasonable limits. Because of this, he would likely view with distaste the permanent American military deployments around the world, such that which exists in South Korea.
The Korean War raged from 1950 to 1953, resulting in more than 36,000 American deaths, not to mention the deaths of millions of Koreans. For more than half a century since the armistice that ended the fighting, American troops have remained deployed along the Demilitarized Zone guarding against the possibility of another North Korean attack on South Korea.
While the number of American service personnel has been reduced in recent years, it remains substantial. All told, 26,000 American men and women are serving in uniform in South Korea, primarily in the 2nd Infantry Division and the 7th Air Force. One of the foreign policy goals of the Obama administration should be a program to gradually reduce this military presence, with a view to abolishing it completely by the end of the Obama presidency.
South Korea is fully capable of defending itself from a North Korean attack. It has 600,000 active soldiers, with a massive force of 4,500,000 in ready reserve. Compared to these numbers, the 26,000 American personnel are just a drop of water in a bucket, clearly there for political purposes rather than military ones. Furthermore, from a qualitative point of view, the South Koreans are superior to their North Korean foes in virtually every respect. If the North Koreans were to attack, it is quite clear that the South Koreans can defend themselves without having American troops on the ground.
In the event of a Second Korean War, the important aid that the United States could provide to South Korea would involve logistical support, with perhaps some naval and air involvement. Being ready to provide this does not require having a large and permanent presence on South Korea soil.
It can be argued that the United States presence in South Korea actually hurts American interests and the overall stability of East Asia. Firstly, it has been pointed out that having thousands of Americans within range of 11,000 North Korean artillery pieces, not to mention a potential nuclear weapon, raises the possibility of the world's largest hostage crisis. Furthermore, the people of South Korea seem decidedly opposed to the continuation of the American presence. A recent study found that South Korean military cadets consider the United States a greater enemy than North Korea. Polls show strong support for an American withdrawal, and doing so would help combat the disturbing trend of increasing anti-Americanism in South Korea and the wider East Asian region.
It is also worth considering the financial burden on the American taxpayer caused by the military presence in South Korea. Recently announced base improvements will, by themselves, cost roughly $10 billion. At a time when the federal budget of the United States is facing severe pressure from so many different directions, it is clear that the bloated American military establishment must be substantially reduced. First on the list of military reductions should be the unnecessary presence in South Korea.