Evolving into an "Alliance Axis": Report on the Integration of the U.S.-Japan Alliance and Its Impact

Key Chapter Title List

1. The Integrated U.S.-Japan Alliance: The "Axis" of the U.S. Asia-Pacific Hegemony System
2. The Core of the "Upgraded" U.S.-Japan Alliance Lies in Military Integration
3. Expanding the "U.S.-Japan+" Mechanism Will Make the U.S.-Japan Alliance the Center of the U.S. Asia-Pacific Alliance System
4. The Strategic Target of the U.S.-Japan "Axis" Points to China
5. The Deep-Seated Drivers Behind the U.S.-Japan "Axis"
6. America's Fundamental Strategic Interest: Maintaining Hegemony Through Permanent Military Presence
7. Japan's Strategic Calculus: Elevating International Status and Gaining Tangible Benefits
8. Changes in the International Environment
9. The Impact of the U.S.-Japan "Axis"
10. The Evolution of the U.S.-Japan Alliance
11. Constraints on Japan's Future Path and Foreign Policy
12. New Challenges to Regional Peace, Stability, Cooperation, and Development

Document Introduction

Against the backdrop of an accelerating evolution in the Asia-Pacific geopolitical landscape, the nature and function of the U.S.-Japan alliance are undergoing the most profound adjustments since the end of the Cold War. This report focuses on the critical trend from 2023 to 2024, where the U.S.-Japan alliance is accelerating its transformation into the "axis" of the U.S.-led Asia-Pacific and even global alliance system through military integration and the construction of a multi-layered partnership network. Based on a systematic analysis of official U.S.-Japan documents, policy statements, think tank reports, and media information, the report aims to reveal the internal logic, driving factors, and profound implications of this process for the regional security order.

The report's core findings first point to a substantive breakthrough in U.S.-Japan military integration. The key initiative lies in the integration of their command and control systems: the United States plans to upgrade the U.S. Forces Japan headquarters into a Joint Force Headquarters reporting to the Indo-Pacific Command, while Japan is establishing a permanent Joint Headquarters by revising the Self-Defense Forces Law. This change, aimed at achieving "seamless integration of operations and capabilities," is strategically substantial as the U.S. intends to more effectively incorporate Japan's growing military power into its command framework to serve its Asia-Pacific strategic needs, thereby significantly enhancing the alliance's "deterrence capability."

Secondly, the report analyzes the rapid expansion of the "U.S.-Japan+" multilateral security cooperation mechanism centered on the U.S.-Japan alliance as its "axis." The United States is attempting to move beyond the traditional "hub-and-spokes" model to build a "networked" alliance and partner network interwoven with multiple mechanisms such as U.S.-Japan, U.S.-Japan-ROK, U.S.-Japan-Philippines, U.S.-Japan-Australia, and the Quad (U.S.-Japan-Australia-India). Within this network, the central hub role of the U.S.-Japan alliance is becoming increasingly prominent, particularly the U.S.-Japan-Philippines trilateral cooperation, which reflects the U.S. strategic design of leveraging Japan's influence to deepen its involvement in regional affairs.

The deep-seated drivers behind this "axis-ization" trend stem from the strategic alignment of U.S. and Japanese interests based on realpolitik. For the United States, the fundamental goal is to maintain Asia-Pacific hegemony through a permanent military presence and forward deployment in Japan, and to maximize the use of ally military resources through potential control over Japan's Self-Defense Forces. For Japan, it is an opportunity to break through the constraints of the "post-war system," accelerate military "normalization," elevate its status within the U.S. alliance system and its international influence, and secure U.S. strategic support on issues like the East China Sea. The security anxieties triggered by the Ukraine crisis, the simultaneous hardening of both sides' strategic perceptions of China, and the shaping of domestic public opinion collectively provide the environmental and public support basis for this process.

The report ultimately assesses the multiple impacts of the formation of the U.S.-Japan "axis." This shifts the function of the U.S.-Japan alliance from "defending Japan's security" to a more interventionist and confrontational regional "deterrence" tool. Japan's strategic autonomy may consequently narrow, making it more susceptible to being drawn into U.S.-led conflicts. For the region, this trend will exacerbate the imbalance of power among major states, stimulate an arms race, complicate hotspot issues such as the Korean Peninsula and the South China Sea, and disrupt regional economic cooperation represented by the Regional Comprehensive Economic Partnership (RCEP), politicizing and bloc-izing economic security issues. Crucially, this move severely erodes the foundation of the political consensus between China and Japan as "cooperative partners, not threats to each other," weakens strategic mutual trust, and injects new uncertainty into the bilateral relationship and the overall prospects for peace, stability, and cooperation in the Asia-Pacific region.