The Development of Regional Security Architecture:
From Asia-Pacific to Indo-Pacific

Ken Jimbo
Keio University

The Three-Tiered Structure of Regional Security

In the early 2010s, the present author and his peers advocated the importance of conceiving security in the Asia-Pacific region as an "architecture." 1 Then, we tentatively defined regional security architecture as follows: "Taking the distribution of power in a given region as the fundamental component, the overall structure of interrelationships between alliances, functional cooperation, and regional cooperation formed among the main actors who have common interests in regional security to achieve clear objectives." We propounded it as a concept for policy analysis of security in the Asia-Pacific. The Asia-Pacific security architecture has three layers: (1) the US bilateral alliance networks (the first layer); (2) ad hoc cooperation formed by security issues (the second layer); and (3) regionwide security cooperation (the third layer). We thought it important to take up these three layers as analytical concepts and to understand their interrelationships. 2

First, the hub-and-spokes bilateral alliances with the United States and their networks [the first layer]. From the end of World War II to the Cold War era, the United States shaped the security order in the Asia-Pacific region through the bilateral alliance system (US-Japan, US-ROK, US-Australia, US-Philippines, and US-Thailand relationships). From the post-Cold War period to the present day, the US-centered "hub-and-spokes" bilateral relationships have gradually evolved into cooperation among allies and partner countries (spokes) while increasing collaboration with non-allied actors based on existing alliances. This trend is a phenomenon known as "networking."

Second, the formation of diverse ad hoc security cooperation by security issues [the second layer]. In other words, it is the formation of flexible cooperative relationships not necessarily constrained by the distribution of power, geographical concepts, or existing institutions but based on the sharing of common security issues. For example, concerning cooperation on non-traditional security issues (disaster relief, humanitarian assistance, collaboration against international organized crimes and terrorism, health and sanitation, etc.) in the Asia-Pacific region, flexible cooperation packages have been formed among regional countries. What is particularly distinctive in relation to regional security architecture is that the importance of [the second layer], which failed to be sufficiently focused, has become highlighted.

Thirdly, the gradual institutionalization of regional security cooperation [the third layer]. The Asia-Pacific region had long lacked an institution for comprehensive security cooperation. However, regular meetings at the level of heads of state, foreign ministers, and defense ministers have now come to be convened: the ASEAN Regional Forum (ARF) established in 1994, the East Asia Summit (EAS) established in 2005, and the expanded ASEAN Defense Ministers' Meeting (ADMM Plus), which greatly expanded the number of participating countries in 2010. In addition, the Shanghai Cooperation Organization (SCO) established in 2001 and the Conference on Interaction and Confidence-Building Measures in Asia (CICA), which instituted summit meetings in 2002, have enlarged their functions as institutions for wider security cooperation, joined by China, Russia, and some other countries in Central Asia, South Asia, and the Middle East.

Changes in the "Three-Tiered" Security Architecture

A regional security architecture will change depending on the transformation of the security environment and the security capabilities and intentions of regional players. A few years after the present author proposed a system of understanding based on the Asia-Pacific regional security architecture mentioned at the beginning of this paper, the interaction of checks and cooperation was observed in the Asia-Pacific regional security architecture against the background of the rise of China in Asia and territorial disputes and maritime tensions in the East and South China Seas.

What was most noteworthy about the Asia-Pacific regional situation around 2015 was the "rebalancing" policy pursued by the Obama administration. The Obama administration rebalanced its defense strategy toward the Asia-Pacific region, emphasizing alliances as the foundation for regional security, and announced increased cooperation with partner countries. 3 According to the description of the US National Military Strategy and other documents, the three key concepts of "geographical dispersion, operational resilience, and political sustainability" emerged for rebuilding the US military posture. 4 The "geographical dispersion" means a presence that allows the US forces operational access not merely to Northeast Asia but also to the entire Asia as a whole. This concept represents not only the stationing of US military units but also "a presence with a more dynamic character" such as rotational deployment and joint exercises. 5

In the meantime, the "Guidelines for Japan-US Defense Cooperation" released in April 2015 articulates that Japan and the United States will "take measures to ensure Japan's peace and security in a seamless manner at any stage from peacetime to emergencies." The document also emphasizes the promotion of seamless alliance cooperation and the enhancement of cooperation with other allies and partner countries. 6 The June 2014 US-Australia Summit agreed to closer defense and security cooperation between Australia and the United States; in August 2014, the two allies signed the Force Posture Agreement between Australia and the United States at the Australia-US Ministerial Consultations (AUSMIN). 7 The agreement provides a legal basis and a financial burden-sharing framework for the rotational deployment of US Marines, emphasizing the enhancement of joint training and exercises between US military units and the Australian military. In May 2014, the United States and the Philippines signed the Enhanced Defense Cooperation Agreement (EDCA), which calls for strengthening US-Philippine joint military operations and improving the capabilities of the Philippine Armed Forces. 8 The Agreement has enabled the rotational deployment of US forces and the construction of US military facilities in the Philippines, urging both countries to strengthen the activities of humanitarian assistance and disaster relief and to increase opportunities for bilateral training.

In summary, in [the first layer], efforts were made to seek "geographical dispersion" to ensure US operational access, as the relationships between the United States and its allies deepened. As for the maritime security challenges faced by US allies, they were encouraged to improve their capabilities of addressing and managing those challenges. On the other hand, capacity-building assistance for partner countries (especially the ASEAN coastal countries) has emerged as a vital issue demanding US attention.

In [the second layer], ad hoc cooperation progressed in the areas of (1) humanitarian assistance and disaster relief (HA/DR) and (2) maritime security. In response to Typhoon Haiyan, which struck the central Philippines on November 8, 2013, causing tremendous damage, military officials from as many as 20 countries were dispatched to the affected areas to provide restoration and humanitarian assistance. The US military dispatched the aircraft carrier USS George Washington and the landing ship USS German Town; US Marines who operated on land and supportive naval and air forces numbered 13,000 at the time of maximum deployment. Given the probability that large-scale natural disasters will occur with a certain frequency in Asia, regional cooperation in HA/DR will increase. Furthermore, such cooperation will, instead of continuing to be ad hoc, will likely become permanent and institutionalized in [the first and third layers].

The most significant developments in the institutionalization of regional security cooperation [the third layer] are the ASEAN Defense Ministers' Meeting (ADMM) and the expanded ASEAN Defense Ministers' Meeting (ADMM Plus). At the 2013 ADMM, the defense ministers of ASEAN countries agreed to establish a regional logistics support framework to promote cooperation in HA/DR. The defense authorities of ASEAN countries are assumed to mutually provide fuel, food, and water and to cooperate in waste disposal.

At the ADMM Plus meeting in August 2013, the participants agreed to convene every two years instead of every three years and to build a platform for closer cooperation among defense officials participating in the ADMM Plus. In addition, they established Expert Working Groups (EWGs) in six areas of HA/DR, maritime security, defense medicine, anti-terrorism, peacekeeping operations, and mine clearance. The ADMM Plus member states agreed to plan and implement joint drills to advance these efforts more effectively.

The Indo-Pacific and "Security Architecture"

A significant change in regional security since the 2020s is the emergence of the "Indo-Pacific" concept. The Indo-Pacific has been attracting attention since the mid-2000s as a wider concept that links the Indian and Pacific Oceans. Endorsed, in due course, by the "Free and Open Indo-Pacific Strategy" that Japan and the United States launched in 2016-17, the Indo-Pacific came to be viewed as representing a new "magnetism" that affects India, Australia, ASEAN, and far away Europe.

From a security perspective, the regional concept of the Indo-Pacific had a significant background. China's military rise and maritime expansion (in the East and South China Seas and the Indian Ocean) obliged Japan, the United States, Australia, India, and some Southeast Asian countries to face converged security challenges common to them. Strategic dialogues and joint exercises were actively conducted to deal with security challenges in the sea areas vital to those countries. The US Pacific Command changed its name to the Indo-Pacific Command in June 2018. It holds a large area of responsibility (AOR) covering from the Western Pacific to the Indian Ocean. Alignment with key allies and partner countries has increased its strategic integration. The US Indo-Pacific Command now plays a substantial role in the Indo-Pacific region.

The Indo-Pacific Strategic Report released by the US Department of Defense (June 2019) states that the Indo-Pacific is the "most consequential theater" for the future of the United States; the DOD also positions it as the "primary theater." 9 Meanwhile, the "free and open Indo-Pacific," initiated by the Japanese government, includes the "two continents" (Asia and Africa) and the "two oceans" (the Pacific and Indian Oceans) in its geographic scope. The concept aims to promote fundamental principles (the rule of law, freedom of navigation, and the entrenchment and promotion of free trade) and to pursue economic prosperity (physical connectivity, human connectivity, and institutional connectivity). Regarding ensuring peace and stability, it states that, in particular, capacity-building assistance and humanitarian assistance/disaster relief (HA/DR) should be promoted. 10

The Indo-Pacific initiative has functioned as a new "magnetism" drawing European countries into engagement with the Indo-Pacific region. In June 2019, France released a policy paper titled "France and Security in the Indo-Pacific," stating that she will maintain overseas territories and vast exclusive economic zones in the Indo-Pacific to strengthen regional security and the strategic autonomy of regional countries. 11 The United Kingdom also maintains security alignment with other Commonwealth countries through the Five Power Defence Arrangements (FPDA); she is increasing the dispatch of naval vessels and opportunities for joint exercises in the Indian Ocean, the Malacca Strait, and the South China Sea.

The ASEAN also released the "ASEAN Outlook on the Indo-Pacific" at its June 2019 summit. 12 The ASEAN Outlook, adopted after many twists and turns, underscores the connectivity and inclusiveness of the Indo-Pacific, advocates restraints on superpower rivalry, and emphasizes its centrality and strategic role as a mediator. Regarding maritime cooperation, there is some mention of security and the ensuring of freedom of navigation and overflight.

How can we evaluate the above developments from the perspective of regional security architecture? In the Indo-Pacific, the US alliances in [the first layer] are unlikely to expand to the entire Indo-Pacific region immediately as an institution. As for regionwide security cooperation frameworks (e.g., the ARF and the ADMM Plus) in [the third layer], South Asian countries have already participated in those frameworks --- India: ARF and ADMM Plus, Pakistan and Sri Lanka: ARF. Therefore, the Indo-Pacific regional security cooperation frameworks have effectively come into being. However, there is no consensus among the regional countries that security cooperation should be institutionalized as an "Indo-Pacific" regionwide framework --- for example, they have, so far, failed to reach a consensus to make participant countries in the ADMM Plus and those in the ARF identical.

The core of the security cooperation unfolding in the Indo-Pacific should be considered to comprise the regional development of US alliance and partnership activities [the first layer] and the expansion of non-institutional, ad hoc cooperation among the regional countries on a bilateral and multilateral basis [the second layer]. The current state of the Indo-Pacific security cooperation includes the activation of joint training and exercises, high-level exchanges, and military branch exchanges associated with maritime security, capacity-building assistance, and defense equipment and technology cooperation. These efforts are gradually becoming more regular and institutionalized.

The First Layer: Regional Development of US Alliance-Partner Relationships

The US-Japan Security Consultative Committee (2+2) held in April 2019 emphasized that the United States and Japan would realize the shared vision of a "free and open Indo-Pacific" while positioning the US-Japan alliance as "the cornerstone of peace, security, and prosperity in the Indo-Pacific region." 13 According to the US-Japan Security Consultative Committee 2019 Fact Sheet ("III. Working with Partners for a Free and Open Indo-Pacific"), the Committee stresses the following four points: (1) commitment to multilateral cooperation in Southeast Asia through joint training and exercises, capacity building, defense equipment and technology cooperation, and support for ASEAN-related architecture; (2) continued cooperation among the United States, Japan, and Australia and the importance of trilateral joint exercises and capacity building in Southeast Asian and Pacific island countries; (3) the US-Japan-India trilateral cooperation (joint exercises, such as Malabar 2018 and Cope India 2018); and (4) the regularization of quadrilateral engagement among Japan, the United States, Australia, and India. 14

In the past, the US-Japan Security Consultative Committee reiterated the importance of security and defense cooperation with regional countries through "trilateral and multilateral cooperation." But the above joint statement is noteworthy in that it specifically underscores US-Japan-India cooperation and US-Japan-Australia-India (Quad) cooperation while conceiving the Indo-Pacific as a pivot region. This recognition comes from the advancement of bilateral security relationships between Japan, the United States, and Australia (the trilateral cooperation) and between Japan, the United States, Australia, and India (Quad cooperation). From the "hub-spokes" relationships between the United States and its allies, "inter-spoke cooperation" has gradually developed since the 2000s, which has formed the basis for broader alignment in the Indo-Pacific region.

A joint maritime exercise Malabar, the mainstay of security cooperation between Japan, the United States, and India, was originally a bilateral exercise between the United States and India; Japan officially joined it in 2015. The three countries conduct anti-air warfare, surface warfare, mine warfare drills, and special mine-sweeping drills to improve the interoperability of their navies.

The US-Japan-Australia-India (Quad) cooperation is also gradually becoming substantial. In November 2017, the United States, Australia, Japan, and India's diplomatic authorities held a director-general-level strategic dialogue in Manila after an interval of ten years. At its May 2019 meeting, the four countries confirmed their "intention to continue regular consultations." 15 In January 2018, a Quad defense authorities dialogue was convened in India. It was participated by Japan Self-Defense Force Chief of Staff, Joint Staff, Admiral Katsutoshi Kawano; US Pacific Command Commander Admiral Harry B. Harris, Jr; Chairman of the Indian Chiefs of Staff Committee and Chief of the Naval Staff Admiral Sunil Lanba; and Australian Navy Chief Vice-Admiral Tim Barrett. Taking the opportunity of a UN General Assembly meeting in September 2019, the four countries held their first meeting of foreign ministers in New York. 16

The Second Layer: Expanding Ad Hoc Security Cooperation by Issue Area

Another trend of the Indo-Pacific security cooperation is the expansion of ad hoc cooperation by category and area. In particular, cooperation on maritime issues and humanitarian assistance/disaster relief (HA/DR) is characteristically undertaken by countries sharing common intentions and capabilities, beyond alliance and partnership cooperation in the first layer. The countries in the Indo-Pacific region are improving their mutual interoperability and enhancing their military capabilities and proficiency through, among other things, increased consultations between military officials and participation in joint training and exercises. Moreover, the regional countries are using ad hoc security cooperation as a tool for advancing mutual relationships over security challenges (advance cooperation with countries of concern) and for hedging (improve counter-capabilities against countries of concern). 17

These bilateral and multilateral joint training and exercises are of a great variety, including (1) US military-led multilateral frameworks (Cobra Gold, Pacific Partnership, Khaan Quest, etc.); (2) frameworks led by regional countries (Komodo, Kakadu, La Perouse, various joint exercises among ASEAN countries, etc.); and (3) joint exercises aimed at advancing mutual relations with China (China-ASEAN joint maritime exercises/maritime chart exercises, China-Malaysia-Thailand joint military exercises, etc.). In addition, ad hoc joint exercises with coastal states, taking the opportunity of naval vessels' distant-sea voyages and strategic port calls for defense exchanges, are promoted as part of presence operations.

Such bilateral and multilateral functional cooperation will provide the basis for regionwide security cooperation (the third layer). The ADMM Plus established an Expert Working Group (EWG) in each of the six areas of HA/DR, maritime security, defense medicine, anti-terrorism, peacekeeping operations, and mine clearance. Afterward, the ADMM Plus has expanded the scope of practical exercises to include defense medicine practical exercises, disaster relief exercises, and joint maritime exercises. Although the ADMM Plus still has a long way to go to play an effective role in the situations where actual HA/DR is required, it is noteworthy that a framework has come into existence for regionwide sharing of achievements and experiences accumulated through ad hoc cooperation.

As part of security cooperation in the second layer, capacity building has become increasingly important in recent years. Capacity building is a concept that refers to a broad scope of activities that help improve partner countries' capabilities in national defense. (The definition by the Japanese Ministry of Defense (MoD) is focused more specifically on "human resource development and technical assistance in security and technology-related fields.") 18 Behind the emergence of capacity building as a crucial policy measure are the growing autonomous roles of small and medium-sized states in nontraditional security domains (humanitarian assistance, disaster relief, piracy, cross-border crime, etc.) and the increasing importance of enhancing maritime security capabilities --- maritime law enforcement and maritime domain awareness (MDA) --- of those countries.

The MoD's Medium Term Defense Program (FY2019-FY2023) states, "Japan will work with countries of the Indo-Pacific region to support advance capacity development efforts based on their voluntary ownership, so as to enable counterpart military organizations to contribute further towards international peace and regional stability." 19 The Japanese government has pledged to provide patrol vessels to the Philippine Coast Guard to strengthen its maritime law enforcement capabilities; patrol boats to the Sri Lankan Coast Guard and the Djibouti Coast Guard; and three-year aid worth about $500 million to support maritime security capacity building in coastal states in the Indo-Pacific region.


An attempt to reconsider security in Asia from the perspective of regional security architecture provides an analytical framework that helps categorize the objectives, functions, and roles of security systems and understand their interactions. The discourse on the Asian security architecture will, through comparison with the European security architecture, highlight differences between the two security architectures. The NATO collective defense system; the expansion of the NATO's mission and membership; NATO's organizational reforms, and the role of the interrelationships between the EU and the Organization for Security and Co​-operation in Europe (OSCE) --- these are sufficient to convince oneself that it is erroneous to represent the recent progress of security cooperation in Asia as indicating an "Asian version of NATO." Such an understanding would make one overlook some embryonic changes in the current Asian security architecture.

The Indo-Pacific security architecture is still in an embryonic stage and has yet to be discussed in its entirety. However, as major actors are gradually accepting and disseminating the "Indo-Pacific" as a policy concept, it is undoubtedly diminishing its importance as a strategic space. The future formation of the Indo-Pacific architecture will depend on the progress of bilateral and multilateral security cooperation and its institutionalization.

(This paper was translated into English by Tsutomu Inuzuka, SSDP Associate.)

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