December 19, 2025
SEOUL – The US Senate has approved a sweeping annual defense policy bill that reinforces restrictions on any unilateral reduction of US Forces Korea and tightens conditions on the transfer of wartime operational control, underscoring Washington’s insistence that alliance-related changes be guided by security conditions rather than political timelines.
The upper chamber on Wednesday passed the National Defense Authorization Act for fiscal year 2026 by a 77–20 vote, one week after the bill cleared the House of Representatives. The legislation will take effect once signed by US President Donald Trump.
Under the bill, funds authorized by Congress cannot be used to reduce the current 28,500-strong US Forces Korea unless the administration certifies that such a move serves US national security interests and follows appropriate consultations with allies, including South Korea. The provision effectively prevents unilateral troop reductions while allowing limited flexibility under strict conditions.
The legislation also imposes restrictions on the use of Defense Department funds for transferring wartime operational control of the combined South Korea–US command. Any transfer that deviates from previously agreed bilateral plans would be prohibited unless the administration certifies to relevant congressional committees that the move aligns with US national security interests and has been sufficiently coordinated with allies, including South Korea, Japan and the United Nations Command. Even then, the restriction would only be lifted 60 days after certification.
The reappearance of language restricting troop drawdowns marks the first such provision in five years. Similar measures were included during the first Trump administration, as lawmakers sought to curb the possibility of abrupt force reductions on the Korean Peninsula.
Beyond Korea, the NDAA introduces parallel safeguards in Europe, stipulating that significant cuts to the roughly 76,000 US troops stationed there must be preceded by consultations with NATO allies. If the Pentagon fails to do so for more than 45 days, the bill mandates an automatic freeze on 25 percent of the defense secretary’s operational and travel budget, though troop reductions remain permissible if allied consent is secured and US security interests are demonstrated.
The legislation authorizes $901 billion in defense spending for the coming fiscal year, with allocations spanning operations and maintenance, personnel costs, procurement, research and development, nuclear programs and military construction. It also funds expanded military exercises with allies and partners in the Indo-Pacific region and earmarks $1 billion for cooperation projects with Taiwan.
At the same time, the bill introduces new restrictions on US investment in sensitive Chinese technologies, including artificial intelligence with potential military applications, while rolling back diversity initiatives and climate-related spending that conservative lawmakers argue undermine combat readiness. The final version excludes a proposal by the Trump administration to rename the Department of Defense the “Department of War.”
Defense analysts say that while the troop-related provisions have drawn the most public attention, the restrictions on wartime operational control may carry greater long-term implications for South Korea’s security posture.
“There is a lot of focus on the size of US Forces Korea, but the issue of the transfer of wartime operational control appears to be more significant,” said Jeon Kyung-joo, a research fellow at the Center for Security and Strategy at the Korea Institute for Defense Analyses, in comments to The Korea Herald.
Yang Uk, a senior research fellow at the Asan Institute for Policy Studies, said that “neither Seoul nor Washington opposes the eventual transfer of wartime operational control in principle,” but warned against placing excessive emphasis on “completing the process within a single presidential term.”
Yang noted that the highest-ranking officer of US Forces Korea has publicly urged the allies to reassess whether agreed conditions can realistically be met. During a recent webinar, Xavier Brunson, who also heads the South Korea–US Combined Forces Command, acknowledged Seoul’s desire to complete the transfer within President Lee’s term but stressed that “we know the start point and we know the endpoint.” He added that while both sides must work to meet the conditions within that window, they must also be prepared to recognize when “we can’t get there from here.”
Yang said the remarks underscore the need for Seoul to remain attentive to the operational assessments of its alliance partner, even as it seeks to accelerate the transition.