Korea and the United States have issued a joint statement that they have agreed on the concept of "strategic flexibility," under which the United States Forces Korea (USFK) could be mobilized for operations outside the Korean peninsular when it deems necessary to the United States beyond its original role to depend South Korea from the possible attacks of the North Korea. This paper focuses on this affair, i.e. on whether such change of USFK`s role from defending forces to keep peace in Korean Peninsular as agreed in the U. S. Korea Mutual Defense Treaty, to advanced troops under U.S.-sglobal troop realignment scheme. That agreement positively accepts the aggressive foreign policy of the Bush Administration and, in result, can be interpreted to allow Korean people to be unintendedly involved in world wide military disputes caused by that Administration. But such It shall be held unconstitutional from several reasons. Firstly, the Korean Constitution has so called "the Peace Clause" that prohibits the Korean armed forces from committing any aggressive war, from which a fundamental rights to peaceful life shall be deduced in combination with the right to pursuit happiness(§10). Such involvement is obviously contradict to these constitutional obligation with result that peoples right to peaceful life shall be seriously infringed, Secondly, if such agreement come to effectively executed, the peace clause will be substantively damaged so as to be same as revised from "the Peace Clause" to "the War Clause". At this point, people shall be deprived of his/her right to participate to revision procedure of the Constitution, which has been recognised by decision of the Constitutional Court. Thirdly, the Constitution provides some meaningful ways for ordinary people to participate to national policy-making processes. Peoples`s right to referendum according to §72 of the Constitution is one of the most democratic ways, which shall, eventually, be denied in this case, because the agreement changes the role not only of the USFK but also of the Korean Armed Forces. Fourthly, taxpayer shall have constitutional right to check and keep his/her money being used for legal and consitutional purposes, The Korean people has paid all the stationing costs of the USFK, in order to get deterring forces against the "invasion" of the North Korea. But, the agreement tries to change unconstitutionally such role of the USFK to that of extraterritorial aggressive forces, which has no direct connection with Korean National Security, which shall seriously infringe the rights of the taxpayers. There are so many reasons that the agreement shall be held unconstitutional, such as infringement of the legislative body`s approval power. Besides, there is no reason that we the people of Korea should be involved such aggressive wars committed by and for the Bush Administration. The best way of resolving international disputes and conflicts is just reconciliation and collaboration based on the spirit of tolerance, not the "anti-terrorism war".