"South Korea is one of the United States' most important strategic and economic partners in Asia. Members of Congress tend to be interested South Korea-related issues for a number of reasons. First, the United States and South Korea have been allies since the early 1950s. Under their military alliance, the United States is committed to helping South Korea defend itself, particularly against any aggression from North Korea. The United States maintains about 28,500 troops in the ROK and South Korea is included under the U.S. 'nuclear umbrella.' Second, Washington and Seoul cooperate over how to deal with the challenges posed by North Korea. Third, South Korea's emergence as a global player on a number of issues has provided greater opportunities for the two countries' governments, businesses, and private organizations to interact and cooperate with one another. Fourth, the two countries' economies are closely entwined and are joined by the Korea-U.S. Free Trade Agreement (KORUS FTA), the United States' second-largest FTA. South Korea is the United States' seventh-largest trading partner. The United States is South Korea's third-largest trading partner. Since late 2008, relations between the United States and South Korea (known officially as the Republic of Korea, or ROK) have been arguably at their best state in decades. Much of the current closeness between Seoul and Washington is due to the convergence of interests between the Obama Administration and the government of former President Lee Myung-bak, who left office at the end of February 2013. The overall U.S.-South Korean relationship is expected to remain healthy under new President Park Geun-hye, although she has hinted at policy moves that could cause intense bilateral discussions, particularly over North Korea policy and the renewal of a civilian nuclear cooperation agreement."
CRS Report for Congress, R41481
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html