Yasuyo Sakata provides a historical overview of US-Japan-ROK defense cooperation in Northeast Asia, from the Korean War to the Camp David Summit, explaining how the trilateral partnership was redefined as an Indo-Pacific partnership and incorporated the “Northeast Asia Anchor.” Sakata argues that Japan and the United States have taken the lead in reconstructing the Indo-Pacific security architecture through their Free and Open Indo-Pacific (FOIP) strategies, and that the US-Japan-ROK trilateral relationship has been incorporated into this framework alongside other alliances such as the Quad and AUKUS. Sakata explores how Korea’s shift back towards the Indo-Pacific under President Yoon’s leadership has allowed for expansion of the scope of US-Japan-ROK trilateral cooperation, as affirmed during the Camp David Summit. However, Sakata contends that a comprehensive defense approach is needed in the Indo-Pacific involving allies and partners to build upon this foundation and strengthen defense and security cooperation amidst the challenges posed by North Korea, the Taiwan Strait, maritime security, cybersecurity, and space. Action is essential, as time is running out to solidify gains from the Camp David Summit and build a stable relationship. Therefore, Sakata argues that Japan and South Korea should strengthen relations deliberately yet cautiously before domestic politics potentially spoil recent progress.