USFK 的传统核心任务源自 1953 年停战后的同盟安排，即吓阻北韩；但美国国防部 12 月 23 日的年度报告称，中国军力正「稳步进展」到可在 2027 年具备入侵台湾所需态势。韩国方面担忧美军被调往第三地，尽管美国防长皮特・赫格塞斯在 11 月访韩时强调仍聚焦「确保 DPRK 对韩威胁不是威胁」。
目前约有 28,000 名美军驻韩，总部在平泽的汉弗莱营，距首尔约 70 公里；兵力集中有助于在东北亚机动，且邻近乌山基地与平泽港便于紧急补给与转运。USFK 于 9 月在群山基地永久部署 MQ-9「死神」无人机（过去多为训练用途），除监控北韩外也可能关注黄海与中国动向。美方同时强调第一岛链（冲绳—台湾—菲律宾）与第二岛链（小笠原—关岛）的战略竞逐，并在 12 月 19 日呼吁韩军更主动参与印太与大型演训；另提及核潜舰建造获批与日本增防费压力，以分担东亚安全负担。
U.S. Forces Korea (USFK) is widening its operational scope beyond the peninsula to sustain a rapid-response posture for a Taiwan contingency, aiming to strengthen deterrence not only against North Korea but also a more assertive China. On Dec. 29, Gen. Xavier T. Brunson framed Korea as a nexus in Northeast Asia’s balance of power, and USFK showcased an “East-Up Map” highlighting distances to Pyongyang, Beijing, Taipei, Manila, and Vladivostok to support “strategic flexibility.”
The alliance’s original focus has been deterring North Korea since the 1953 armistice, but Washington’s reassessment is driven by China’s expanding capabilities. The U.S. Defense Department’s annual report released Dec. 23 said China is making “steady progress” toward a posture that could enable an invasion of Taiwan by 2027. Seoul remains wary that expanded flexibility could divert USFK to a third country, even as Defense Secretary Pete Hegseth said during a November visit that the U.S. is still focused on ensuring the DPRK threat is not a threat to South Korea.
Roughly 28,000 U.S. troops are stationed in South Korea, headquartered at Camp Humphreys in Pyeongtaek about 70 km south of Seoul, positioned for mobility and logistics via nearby Osan Air Base and Pyeongtaek Port. In September, USFK permanently deployed an MQ-9 Reaper to Gunsan for the first time, which could support monitoring beyond North Korea, including China’s activity in the Yellow Sea. The U.S. is also emphasizing the first island chain (Okinawa–Taiwan–Philippines) versus China’s push toward the second island chain (Ogasawara–Guam), while urging a larger South Korean Indo-Pacific role (Dec. 19) and pressing regional partners to increase defense contributions.
