Seoul has gradually adopted a more outspoken position regarding the importance of peace and stability in the Taiwan Strait and framed it in increasingly expansive terms—as a regional and global issue yet also directly linked to the peace and stability of the Korean Peninsula. Nevertheless, the U.S.-ROK alliance faces a gap between such rhetoric and its political, military, and operational preparedness to navigate an actual conflict between the United States and China over Taiwan and the attendant risk of a simultaneous conflict in Korea, including a lack of consensus within the alliance regarding the strategic flexibility of United States Forces Korea (USFK). This article examines these issues in several ways. First, it briefly reviews a 2006 U.S.-ROK understanding regarding the strategic flexibility of U.S. forces stationed on the Korean Peninsula, which was left deliberately vague but catalyzed a broader joint vision study and strategic reconceptualization of the alliance. Second, it focuses on the reemergence in the late 2010s of discussions about USFK’s potential regional use and pressure by Washington on Seoul to embrace a wider role for the alliance amidst worsening U.S.-China relations. Third, it shows how, in the context of Russia’s war in Ukraine and growing tensions surrounding Taiwan, U.S. officials continued to discuss the potential use of USFK in regional contingencies and traces how the Yoon administration gradually aligned its strategic signaling regarding Taiwan with Washington’s own and embraced the Indo-Pacific concept. Finally, it concludes with several interconnected risks related to the shift in strategic signaling examined here and highlights reasons for Seoul and Washington to enhance communication about the complex challenges they face and proceed with caution.