Expanding the ROK-US alliance to the Indo-Pacific region should be actively pursued. South Korea should take note of the aspect of strengthening the ROK-US alliance and increasing its capabilities for the benefit of South Korea. The development of military technology can be aided by research and development while engaging in military exchanges and cooperation with the United States. The following should be considered as South Korea actively expands the ROK-US alliance to the Indo-Pacific. First, it should be made clear that South Korea is concerned about the excessive number of US troops stationed in South Korea, and that its focus on the Indo-Pacific region does not affect the defense of North Korea. Second, joint research and development of weapons systems with the United States should be carried out while expanding the ROK-US alliance to the Indo-Pacific region. Third, South Korea needs to lay the groundwork for South Korea to secure stable maritime transport routes and receive stable energy in its trade while expanding the ROK-US alliance to the Indo-Pacific region. It is also important for Korea to upgrade its naval base on Jeju Island as a missile defense system amid the expansion of the Korea-U.S. alliance. Jeju Island can significantly reduce accidental clashes and checks, as its naval base has already been built and is geographically far from China. It is safe to choose an area as far as possible away from China if Korea needs to build and upgrade its missile defense bases. This is both a way to save the lives of the soldiers involved and to save the lives of local residents. Jeju is in a good position to receive stable and timely supplies of weapons related to the defense industry because it is close to Changwon. And Jeju Island is well positioned to receive stable rice from grain regions such as Jeolla-do and Chungcheong-do. Jeju Island can contribute to the development of a win-win industry if it receives supply from nearby regions because it produces less rice and produces less rice on its own. When Korea builds a missile defense base while upgrading its military base in Jeju, it is important to lay the foundation for win-win development in connection with local industries and develop the local economy.