This paper studied the changes of security in Northeast Asia and its influence to ROK-U.S. Alliance. ROK and U.S. have been expanding its geographical and functional scope of alliance after having agreed upon a strategic alliance for the 21st century. While U.S. has specified and consolidated its extended alliance with South Korea, U.S. also has been promoting support from China over North Korea's nuclear issues. ROK-U.S. Alliance enhanced its consultation, increase its transparency, and understand each other's sensitive concerns. The alliance has endured the difficult times in the past and will continue to maintain its status. The patience, leadership, and wisdom that have traditionally characterized the alliance will continue to be preserved in a perfect form against the nK's provocation.
Nonetheless, those two allies should facilitate their robust support at the regional and global level; should be flexible in choosing the right timing of the WOC transfer; and should manage the alliance to be a lead to the ROK reunification. The ROK and U.S. should also prepare to avoid the divergence of interests when a historic opportunity of reunification comes to the Korean peninsula; and they should focus on their efforts on China so that she will share the vision in which U.S. led alliances and multilateral security cooperation coexist in Northeast Asia.
The ROK-U.S. alliance has endured the difficult times in the past and there are all reasons to believe that it may repeat. Meanwhile, the U.S. can take confidence that its patience, transparency, leadership that have always characterized the relationship in the past will strengthen the alliance.