The emergence of the People’s Republic of China as an increasingly significant military power in the Western Pacific presents major implications for Japan, the U.S.-Japan alliance, and regional security. But a comprehensive assessment of the current and possible future impact of China’s military capabilities and foreign security policies on Tokyo and the alliance, along with a detailed examination of the capacity and willingness of both the United States and Japan to respond to this challenge, is missing from the current debate. Such an analysis is essential for Washington and Tokyo to better evaluate the best approaches for maintaining deterrence credibility and regional stability over the long term.

Key Findings

The most likely potential challenge to the U.S.-Japan alliance over the next fifteen to twenty years does not involve full-scale military conflict between China and Japan or the United States—for example, one originating from Chinese efforts to expel Washington from the region.



 The likeliest challenge instead stems from Beijing’s growing coercive power—increasing Chinese military capabilities could enable Beijing to influence or attempt to resolve disputes with Tokyo in its favor short of military attack.



 An increase in the People’s Liberation Army’s presence in airspace and waters near Japan and disputed territories could also heighten the risk of destabilizing political-military crises.



 Significant absolute and possibly relative shifts in the military balance between China and the alliance in Japan’s vicinity are likely.



 In the most probable future scenarios facing these three actors, the U.S.-Japan alliance will either only narrowly retain military superiority in the airspace and waters near Japan or the balance will become uncertain at best.



 A significant drop in the potential threat posed by China is also possible if the Chinese economy falters and Beijing redirects its attention and resources toward maintaining internal stability.



 More dramatic shifts in the strategic landscape are unlikely in the fifteen- to twenty-year time frame. Such shifts include an Asian cold war pitting a normalized U.S.-Japan alliance against a belligerent China and a major withdrawal of U.S. presence that heralds either the dawning of a Sino-centric Asia or the emergence of intense Sino-Japanese rivalry with Japanese nuclearization.

U.S. and Japanese Policy Responses

There are no “silver bullets.” No regional or alliance response can single-handedly deliver a stable military or political balance at minimal cost to all parties involved. Each of the major conceivable responses to these future challenges in the regional security environment will likely require painful trade-offs and, in some cases, the adoption of radically new ways of thinking about the roles and missions of both the U.S. and Japanese militaries.

Three general political-military responses offer viable ways to advance allied interests over the long term.

Robust Forward Presence: This deterrence-centered response is designed to retain unambiguous allied regional primacy through either highly ambitious and forward-deployment-based military concepts, such as Air-Sea Battle, or approaches more oriented toward long-range blockades, such as Offshore Control.



Conditional Offense/Defense: This primacy-oriented response nonetheless avoids both preemptive, deep strikes against the Chinese mainland or obvious containment-type blockades and stresses both deterrence and reassurance in a more equal manner.



Defensive Balancing: This response emphasizes mutual area denial, places a greater reliance on lower visibility and rear-deployed forces, and aims to establish a more genuinely balanced and cooperative power relationship with China in the Western Pacific.

These responses could be complicated by a number of factors.

Limits on the ability of Japan or other nations in the Asia-Pacific region to advance substantive security cooperation or embark on major security enhancements



 Unwillingness in the U.S. military to alter doctrinal assumptions in operating in the Western Pacific  China’s own suspicions of alliance efforts that might constrain the use of its growing capabilities



Low tolerance among stakeholders for uncertainty and even failure during political or diplomatic negotiations over vital security interests

The status quo is likely to prove unsustainable. Despite the potential complications, Washington and Tokyo must seriously evaluate these possible responses. Current economic and military trends in China, Japan, and the United States suggest that existing policies and strategies might fail to ensure a stable security environment conducive to U.S. and Japanese interests over the long term.

Advance Praise

“The Asia century is well under way, and with it the emerging challenges of a region in transition…. Any sound future policy will require a thorough assessment of China’s evolving military and foreign security capabilities and of the capacity and willingness of Tokyo and Washington to sustain their historic cooperation. There are no guarantees that the future will resemble the recent past, and the best approaches for continued deterrence credibility and regional stability will require careful consideration and thoughtful analysis.

To this end, the Carnegie Endowment has offered up an extraordinary contribution: China’s Military and the U.S.-Japan Alliance in 2030: A Strategic Net Assessment. The future security and prosperity of the Asia-Pacific region may very well be defined by the content of this assessment. But one thing is certain: the United States and Japan must recognize that in the future, status quo thinking is unlikely to guarantee a stable security environment that serves the long-term interests of the bilateral relationship or the region.”

—Governor Jon Huntsman Jr., former ambassador to China and former governor of Utah

“Michael Swaine and his co-authors have done an admirable job of thinking through the complex interactions of the U.S.-Japan-China relationship in the future. Using scenarios and trend projections, they go beyond simple predictions to examine the complex interactions of different developments and reactions among the three countries and different groups within them. While I do not agree with specific military and policy judgments in all the scenarios, I strongly endorse the effort to examine potential developments along with likely and possible reactions and counterreactions. The triangular interactive relations among these great Asian powers will determine both the overall future of the region and much of the futures of each of the individual countries.”

—Admiral Dennis Blair (U.S. Navy, retired), former director of national intelligence and former commander of the U.S. Pacific Command

“The U.S.-Japan alliance has long been crucial to the military balance in the Western Pacific. The balance of power in the region is now shifting toward China, and tensions between Asian states are rising concomitantly. Current trends suggest that the United States and Japan will not find it easy to sustain immunity from coercion as they seek to preserve stability, secure their national interests, and manage crises in the region over the coming years. This study is a remarkably timely, thoughtful, and meticulous examination of the drivers and choices the allies will face through 2030. It illuminates probable shifts in the strategic landscape of northeast Asia, their consequences, and the policy and resource allocation choices they pose. In this strategic net assessment, the scholars Carnegie assembled have given decisionmakers in Tokyo and Washington a uniquely insightful and thought-provoking policy-planning tool.”

—Ambassador Chas W. Freeman Jr. (U.S. Foreign Service, retired), former assistant secretary of defense

“There is nothing out there like this—a very important piece of work…. This is an elegantly framed study that systematically assesses the postures of China, Japan, and the United States and treats the dynamics between them. Obviously, this is tough to execute, but the authors have done an outstanding job. The report addresses a critical subject and offers empirically based suggestions…. There is nothing like it in terms of looking at the interactions between states to produce a set of possible future regional dynamics.”

—Eric Heginbotham, senior political scientist at the RAND Corporation

The authors would like to thank the Japan Ground Self Defense Forces Research and Development Command NAT Project for translating the executive summary into Japanese.