Mutual Defense Treaty Between the United States and the Republic of Korea
Parties:
Article II
The Parties will consult together whenever, in the opinion of either of them, the political independence or security of either of the Parties is threatened by external armed attack. Separately and jointly, by self help and mutual aid, the Parties will maintain and develop appropriate means to deter armed attack and will take suitable measures in consultation and agreement to implement this Treaty and to further its purposes.
Article III
Each Party recognizes that an armed attack in the Pacific area on either of the Parties in territories now under their respective administrative control, or hereafter recognized by one of the Parties as lawfully brought under the administrative control of the other, would be dangerous to its own peace and safety and declares that it would act to meet the common danger in accordance with its constitutional processes.
Link to Treaty:
http://avalon.law.yale.edu/20th_century/kor001.asp