Cover: The Thickening Web of Asian Security Cooperation

The Thickening Web of Asian Security Cooperation

Deepening Defense Ties Among U.S. Allies and Partners in the Indo-Pacific

Published Aug 29, 2019

by Scott W. Harold, Derek Grossman, Brian Harding, Jeffrey W. Hornung, Gregory Poling, Jeffrey Smith, Meagan L. Smith


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Research Questions

  1. What sorts of new or expanded defense activities have U.S. allies and security partners in the Indo-Pacific pursued over roughly the last two decades?
  2. Why are these actors cooperating in new areas and/or elevating their engagements in existing spaces?
  3. What are the implications of these new or expanded types of defense cooperation for U.S. national security and regional stability?
  4. Do these activities derive from concerns about China's rise, perceptions of U.S. decline or wavering commitment, growing public expectations, rising costs of defense industrial development, or other factors?

Key U.S. allies, security partners, and diplomatic interlocutors in the Indo-Pacific have been establishing or deepening their defense ties by branching out, engaging with each other on high-level security consultations, selling or transferring defense articles, engaging in joint defense industrial development, carrying out bilateral training and exercises, and signing defense-related agreements. Today, these nations — Australia, Japan, the Philippines, and South Korea — are also cooperating with such non–U.S.-treaty countries as India, Indonesia, and Vietnam, which have aligned themselves more closely with the United States as China has grown both more powerful and more assertive in recent years. As a consequence, a set of important new linkages and security commitments among regional actors is forming, with substantial consequences for the United States, China, and the Indo-Pacific region.

This report highlights the extent to which regional actors' security initiatives are a response to the perceived threat posed by a rising, assertive China. This report also calls attention to the strong support that the United States continues to enjoy across the region, with numerous actors expanding their security partnerships out of a desire to reinforce the existing regional order centered on a set of U.S. alliances so as to help share the burdens of security maintenance. The analysis points out the importance of understanding the diverse motivations that regional actors have for expanding and deepening their regional security partnerships, and it highlights key areas for building partner capacity. Finally, the authors clarify which aspects of deepening security relationships derive from concerns about China and which stem from considerations other than balancing.

Key Findings

History, identity, and norms shape defense cooperation

  • Prior experience with colonization has left a legacy of sensitivity to alliance, perceived loss of autonomy, or dependence on a foreign power.
  • Post–World War II identities are changing (e.g., Japan and South Korea).
  • A country's identity as a great or rising power (e.g., India, Japan, and South Korea) is important.

State capacity and military capabilities are key drivers

  • The resources devoted to external military cooperation can empower or constrain defense ties with a country's regional partners.
  • Training, exercises, and exchanges can build critically important personal relationships.

Counterterrorism, intelligence sharing, and cyber and maritime law enforcement are paving the way for expanded cooperation

  • There is substantial sensitivity in the region to being perceived as cooperating more deeply in the military and security domains when framed as a reaction to China's growing power and assertiveness.
  • Countries have deepened security links by starting with or building up from counterterrorism cooperation.
  • In Southeast Asia, counterpiracy efforts and cooperative efforts to counter illegal fishing, drug trafficking, and human smuggling provide routes for deepening security cooperation.

Deepening ties with nonaligned partners is a worthy goal

  • Deepening ties may facilitate a greater alignment with the United States if other Asian countries, such as Japan, South Korea, or the Philippines, take the lead in deepening ties with such countries as India, Indonesia, and Vietnam.


  • U.S. policymakers should recognize the net positive in terms of national security and regional stability to be gained from countries in the region cooperating more than ever before on defense.
  • Clarifying which cooperative efforts derive from factors not tied to Chinese behavior will provide clues about what might not work along with an understanding of issues important to local actors.
  • U.S. policy should focus attention on understanding and supporting important partner nations — such as Indonesia, the Philippines, and Vietnam — whenever their efforts to develop ties with other Indo-Pacific nations can be additive to U.S. aims of building partner capacity.
  • Insofar as Jakarta houses the Association of Southeast Asian Nations (ASEAN) Secretariat and has tended to regard itself as the most important country for ensuring an active institutional ASEAN role in regional affairs, continued cooperative efforts by the United States, in tandem with Australia, Japan, India, and South Korea, should be a high priority.
  • Building on the 2016 Maritime Security Initiative, the United States might consider networking its efforts to build partner capacity through closer coordination with allies and partners to create a regional strategy for helping address gaps in partner countries' intelligence and law enforcement architectures.
  • The United States and its allies are more likely to succeed in these efforts when they share common platforms, which should be embedded in routine training and exercise relationships because such ties are "sticky" and not easily undone through changes resulting from coups or elections.

This research was sponsored by the MacArthur Foundation's Asian Security Initiative and conducted within the International Security and Defense Policy Center of the RAND National Security Research Division (NSRD).

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