This book is coming from Project IV Korean Reunification and After of IKUPD PROJECT: U.S. Security Strategy to Asia. This project is to prepare Korean Reunification in peaceful process and furthermore, the Korean Peninsula’s role to reorganize security structure in Northeast Asia. Nuclear potential as the utmost proof of advanced military techniques in Asia has challenged the U.S. security strategy to Asia that the U.S. should effectively manage the uprising atmosphere and such a vivid symptom to overwhelm U.S. power in Asia. Especially, Northeast Asia is the right place to reveal major power’s military ventures where China and Russia are still dreaming of world power. However, South Korea’s military competition is now pushing up its position to the ranking six in the world military power level. It is a positive sign to upgrade the U.S. and Korea alliance and Korea has a chance to explore its new role in Asia. At this point, effectiveness of Korean Reunification in Korea-U.S. political traits will be investigated and finally, this book finds out Korea’s status in Asia power structure after Korean Reunification as a platform to upgrade Korea-U.S. alliance.