Potential Impact of the 2023 National Security Strategy: The Department of Defense's Prioritization of the Western Hemisphere and China.

Key Chapter Title List

1. Comparison of the 2025 National Security Strategy with Previous Strategies
2. Potential Impacts on the Department of Defense
3. Force Redeployment
4. Procurement Related to Homeland Defense
5. Military Advantage Procurement Targeting China
6. Potential Challenges and Existing Trends in Implementation
7. Issues Facing Congress

Document Introduction

This report aims to analyze the shift in regional priorities outlined in the United States' 2025 National Security Strategy and its potential implications for the Department of Defense's strategies, plans, programs, and operations. This strategy marks a significant adjustment in U.S. foreign policy focus, potentially triggering profound changes in defense resource allocation, global military presence, and alliance partnerships.

The report first compares the similarities and differences between the 2025 strategy and the strategies of the previous Biden administration and the first Trump administration. Unlike the 2017 and 2022 strategies, which emphasized great power competition with China and Russia, the 2025 strategy explicitly aims to defend the U.S. homeland by restoring U.S. preeminence in the Western Hemisphere through reaffirming and enforcing the Monroe Doctrine, while simultaneously engaging in economic and military competition with China in the Indo-Pacific region. The strategy identifies addressing mass migration, drug trafficking, regional foreign incursions, and defending against complex aerial threats using the U.S. GMD missile defense system as core elements of homeland defense. In contrast, its emphasis on competition with Russia, Russia's potential threat to European security, and competition with China and Russia in the Middle East and Africa is reduced.

Based on the strategy text, the report systematically outlines its potential impacts on the Department of Defense, focusing primarily on three areas: First, the global redeployment of forces, which may involve reducing military personnel and equipment in Europe and the Middle East, correspondingly increasing presence in the Western Hemisphere and/or the Indo-Pacific region, and potentially leading to requirements for new construction or expansion of domestic base facilities. Second, a shift in procurement priorities, with homeland defense projects (such as missile defense systems, maritime and aerial surveillance capabilities) and equipment aimed at gaining military advantage over China receiving priority. The latter specifically includes long-range manned/unmanned platforms and weapons capable of operating effectively outside China's Anti-Access/Area Denial (A2/AD) system, platforms capable of operating effectively within it (such as submarines), and long-range logistical capabilities supporting operations in the Western Pacific. Simultaneously, the research, development, and procurement of ground systems (such as armored fighting vehicles, tube artillery) more suited to the European theater may be downgraded.

The report points out that despite clear strategic intent, successive administrations' goals of reducing military presence in specific regions have often faced challenges due to international commitments and unforeseen crises. For example, U.S. treaty obligations to NATO may constrain troop reductions in Europe. However, the report also notes that some potential changes (such as the Navy shifting ships to the Pacific, the Air Force deploying advanced fighter aircraft in the Pacific, the Army and Marine Corps developing land-based anti-ship missiles, etc.) had already commenced before 2025 and may be continued or accelerated under the new strategy.

Finally, the report outlines key oversight and legislative issues for Congress. This includes assessing the impact of force increases and decreases on deterrence stability in various theaters, alliance relationships, and the U.S. ability to respond to regional contingencies; examining the short-term and long-term impacts of shifting procurement priorities on the defense industrial base; considering whether Congress is adequately informed of the administration's global political objectives and defense strategy through channels such as the National Security Strategy and the National Defense Strategy; and analyzing the alignment of the President's budget request with the strategy to decide whether and how to fund capabilities and activities related to implementing the strategy (or other Congressional priorities). Based on an interpretation of the 2025 National Security Strategy text, this report aims to provide an objective and professional analytical foundation for Congressional decision-making.