Countering Maritime Gray Zone Challenges in Southeast Asia: Exploring the Role of ASEAN

Mico Galang

Gray zone coercion challenges are among the security concerns facing the Indo-Asia-Pacific region. Gray zone has been defined as “an effort or series of efforts beyond steady-state deterrence and assurance that attempts to achieve one’s security objectives without resort to direct and sizable use of force. In engaging in a gray zone strategy, an actor seeks to avoid crossing a threshold that results in war.”[i] There are different forms of gray zone coercion tactics, including: information operations and disinformation, political coercion, economic coercion, cyber operations, space operation, proxy support, and provocation by state-controlled forces.[ii] These tactics are not mutually exclusive. Serving as tools in major power competition, some forms of gray zone maybe combined with each other.

Focusing on the maritime domain and using the Power Transition Theory (PTT), the first part of this two-part Executive Policy Brief (EPB) argued that gray zone coercion tactics are part of China’s efforts to alter the status quo in its favor. In order to achieve its strategic objectives while not provoking armed hostilities, Beijing prefers a more incremental approach in challenging the international order. It is in this context that gray zone coercion challenges figure in the regional security environment.

The second part of this two-part EPB shall explore how ASEAN could play a role in countering maritime gray zone challenges. In addition, this paper seeks to answer the following questions: 1) What are the policy complexities in addressing gray zone challenges?; 2) What are the challenges for ASEAN in managing gray zone coercion challenges?; and 3) How can ASEAN’s maritime security-related initiatives help in managing such challenges?

This paper argues that given the geopolitical dynamics at play within ASEAN, and its external relations, the organization’s role in managing gray zone challenges will be limited.

Policy Complexities of Gray Zone

As its name suggests, gray zone coercion is situated between what is generally considered as war and peace. Characterized by asymmetry, ambiguity, and gradualism,[i] addressing gray zone challenges—including in the maritime domain—has a number of interrelated policy complexities, the first of which is that it shows the strengths and weaknesses of the current international order.[ii] On the one hand, the post-World War Two (WWII) international order has, for the most part, created relatively strong norms against outright aggression and territorial expansion.[iii] This then causes some states to resort to gray zone tactics in the first place. But on the other hand, the fact that some states engage in actions below the threshold of armed conflict shows the limitations of the current order in imposing costs on such coercive actions. Indeed, China has expanded its maritime space in the South China Sea (SCS) not by waging an armed campaign by through gray zone coercion.

In addressing gray zone challenges, ambiguity must be both embraced and dispelled.[iv] On the one hand, countering gray zone tactics require development of and investment in similar tools like the coast guard and paramilitary forces. This may allow countries at the receiving end of coercive actions to confront revisionist powers in the gray zone. But on the other hand, countering gray zone challenges also necessitates dispelling ambiguity in order to deny “belligerents the benefits of non-attribution, exposing the nature and illegitimacy of their actions, and raising the various costs—political, diplomatic, economic—of such activities.”[v]  The issue of ambiguity is anchored on another inherent policy complexity—while gray zone coercion tactics seeks to reap the benefits of warfare, the military is only part of the overall response.[vi]

Indeed, gray zone coercion is difficult to deter. The geostrategic predicament in countering gray zone is captured by two observers: “Piecemeal assaults compel the status quo’s defenders to consider unappealing options. They can act first and bear the blame for the outbreak of war, for taking excessive risk, for provoking the revisionist power or for destabilizing the peace. Or, unwilling to incur such costs, they resign themselves to inaction or half-measures. Predisposed to put off difficult decisions, politicians can waffle, and surrender the initiative. Or they can escalate, and see their nation branded a bully.”[vii] Clearly, decision-makers are faced with immense policy choices.

Challenges for ASEAN

As mentioned in first part of this EPB, gray zone challenges are among the major security issues facing ASEAN and broader Indo-Asia-Pacific region. With ASEAN continuously advancing for its centrality in the region’s multilateral security architecture, what challenges does the organization face in addressing – or at least managing – maritime gray zone challenges? The first challenge that ASEAN faces is the different national interests of its member-states. Maritime gray zone coercion – and the SCS dispute more generally – has exposed ASEAN’s internal divisions. After all, of the ten (10) ASEAN member-states (AMS), only four (4) are SCS claimants: Brunei, Malaysia, the Philippines, and Viet Nam.[viii] Among the claimant states, there are competing claims. Viet Nam claims the entirety of both the Paracels, and Spratlys[ix] with parts of the latter being also claimed by the Brunei, Malaysia, and the Philippines.

While most, if not all, AMS have some degree of concerns about China’s increasingly assertive behavior in the region, their strategic calculus is still largely shaped by their respective national interests. Of the four Southeast Asian claimant countries, the Philippines and Viet Nam, as the “frontline states,”[i] are the most vocal, with the two states facing the western seaboard and eastern seaboard of the SCS respectively. Both Viet Nam and the Philippines will lose much of their Exclusive Economic Zones (EEZs), as well as their territorial claims to many SCS features, if China successfully dominates the SCS. Such perspectives maybe at variance with how countries in mainland Southeast Asia views the regional security environment. After all, most mainland Southeast Asian countries have closer geopolitical confluence with China. Indeed, because of the SCS dispute, the Cambodia-hosted 45th ASEAN Foreign Ministers’ Meeting in 2012 was not able to issue joint communiqué—a first in ASEAN’s history.[ii] Former Singaporean ambassador Bilahari Kausikan candidly observed that the incident was “due to the stubborn refusal of the Cambodian [c]hair to consider any text on the SCS that might in the slightest way offend Cambodia’s Chinese patron.”[iii] While some form of nominal consensus has been reached about the issue since the said incident in Cambodia, the SCS continuous to a major security challenge that exposes the varying security interests and perspectives of ASEAN member states.

Divergence in national interest leads to the second major challenge: the difficulty of having a consensus among AMS. Consensus, it must be noted, is effectively defined in ASEAN as unanimity with each AMS exercising a de facto veto power.[iv] Thus, in a system of interaction designed to strengthen the sovereignty of each member-state and in cognizance of their diversity, the “ASEAN Way” has two strategic objectives: 1) to prevent bilateral disputes among between or among AMS to affect regional stability and the ASEAN’s operations; and 2) to avoid contentious issues between AMS and non-AMS to adversely affect relations within ASEAN.[v] However, as a result of unanimity-based decision-making, ASEAN’s initiatives are mostly on non-controversial issues and have focused on the “low-hanging fruits,”[vi] or “lowest common-denominator”[vii] areas of cooperation. Philippine Foreign Secretary Teodoro Locsin Jr has openly complained about the institutional paralysis of ASEAN: “We’re a bunch of guys who always agree with each other on the worthless things.”[viii]

ASEAN and Maritime Security

While maritime security has been in ASEAN’s agenda – particularly of the ADMM and ADMM-Plus – maritime gray zone challenges have not figured prominently in the discussions. Nevertheless, despite ASEAN’s institutional weaknesses and the exposure of its internal divisions, coupled with the dynamics of US-China strategic rivalry, ADMM has nevertheless adopted some initiatives that could modestly contribute to the management of tensions in the SCS, and more broadly complement efforts in addressing traditional security concerns. In 2014, ADMM adopted the Concept Paper on Establishing a Direct Communications Link (DCL)—now called the ASEAN Direct Communications Infrastructure (ADI)—with the purpose of “providing a permanent, rapid, reliable and confidential means by which any two ASEAN [Defense] Ministers may communicate with each other to arrive at mutual decisions in handling crisis or emergency situations, in particular related to maritime security.”[ix] In 2019, the ADMM adopted a concept paper which sought the expansion of the ADI to the Plus-countries.[x]

In 2017, ADMM adopted the Guidelines for Maritime Interaction (GMI), which aims to, among others, “establish comprehensive and feasible maritime conflict management measures on the basis of confidence-building, preventive diplomacy, and peaceful management of tensions that could arise at sea.”[i] GMI notes that it “uphold[s] all existing maritime arrangements between [AMS], as well as between [AMS] and other states and organizations including, but not limited to, [United Nations Convention on the Law of the Sea or UNCLOS] and [Code for Unplanned Encounters at Sea or CUES].”[ii] Albeit voluntary in nature, GMI encourages civil-military dialogue “among [AMS’] naval forces, coast guards, maritime police assets, and private industries engaged in maritime activities.”[iii] Among the activities that could be carried out under the GMI include “discussions on existing strategies, work plans, laws, reports, rules of engagement (ROEs), and other information relevant to maritime security, port security, and overflight jurisdiction; [and] further modalities and procedures.”[iv] Moreover, ADMM opened the possibility of extending the GMI to the Plus countries.[v]

In 2018, ADMM issued the Guidelines for Air Military Encounters (GAME) which, although non-binding and voluntary in nature, aims to apply to “unintentional encounters in flight between military aircraft over high seas, ensuring safe separation to avoid creating a safety hazard. To determine safe separation, military aircraft should comprehensively consider their own national rules, and relevant international guidance.”[i] GAME has four (4) annexes on: Observing Existing Aviation Conventions and Rules; Safe and Professional Communications; Standard Flight Procedures; and Encouraging Mutual Trust and Confidence in the Air.[ii]


Although more work remains to be done, ADI, GMI, and GAME can nevertheless complement existing crisis management mechanisms which aim to prevent and/or deescalate tensions.

To note, ASEAN’s main SCS initiative is the effort to forge a Code of Conduct (COC). Under the 2002 Declaration on Conduct (DOC) of Parties in the SCS, ASEAN and China agreed to the “eventual attainment” of the COC.[iii] While there have been some modest progress in the years since, it was in 2017 that ASEAN and China agreed to a framework for the COC.[iv] The following year, ASEAN and China agreed to a Single Draft SCS COC Negotiating Text (SDNT).[v] Although the COC negotiation process is primarily within the purview of the foreign ministries, the implementation of the adopted COC will largely become the responsibility of the defense establishments of ASEAN and China.[vi] As such, the COC can also affect broader regional defense diplomacy, albeit not ADMM and ADMM-Plus per se. In that negotiating document, Beijing proposed that China and ASEAN should “not hold joint military exercises with countries from outside the region, unless the parties concerned are notified beforehand and express no objection.”[vii] Should this provision be included in the final COC, China could effectively veto military exercises of ASEAN states with other powers such as the US. The Philippines criticized this with the country’s top diplomat stressing that “[Such an agreement would be] implicit recognition of Chinese hegemony….In short, [it is a] manual for living with a hegemon or the care and feeding of a dragon in your living room.”[viii] By the Philippines ended its tenure as the Country Coordinator for ASEAN-China Dialogue Relations, Secretary Locsin expressed that the COC negotiations “went nowhere, [with the Philippines] oppos[ing] the exclusion of any outside power from the [SCS]. That would create a semi-legal sphere of influence repugnant to the comity of all nations.”[ix]

Policy Considerations

Based on the foregoing, it is evident that it is highly unlikely that maritime gray zone coercion challenges would be part of ASEAN’s agenda. The divergent security interests and perceptions among ASEAN states would make achieving a unanimity-based consensus very challenging. Hence, given the challenges facing the COC negotiations, ASEAN’s role will, for now, be limited to the implementation and evaluation of maritime security related initiatives, such as ADI, GMI, and GAME.

In this regard, addressing, or at least managing, maritime gray zone challenges can be done through – apart from individual countries’ initiatives – platforms outside ASEAN. At the national level, there is a need for greater understanding of what maritime gray zones are among concerned government agencies. Since gray zone is situated somewhere between what is generally considered as war and peace, coercive tactics below the threshold of armed conflict are deliberately designed to sow confusion to the enemy on how to respond, what legal regime/protocol would apply, what agency should take the lead, among others. Hence, there is an imperative to have a national consensus on what gray zones are and its implications for the country’s national security.

Indeed, continuing the Armed Forces of the Philippines (AFP) modernization program (AFPMP), as well as the strengthening the country’s maritime domain awareness (MDA) are of national importance. Since gray zone operations do not involve the military alone, there is also a need to boost the capabilities of the Philippine Coast Guard (PCG), and other civilian maritime law enforcement agencies. Continuously monitoring and reporting of developments at sea is crucial. After all, gray zone operations thrive because of the plausible deniability of the deployed forces (e.g. China’s People’s Armed Forces Maritime Militia [PAFMM]).[i] Continuously calling out the activities of these militia forces, which are linked to the People’s Liberation Army (PLA), is important as it could help to diminish it perceived advantage of plausible deniability.

Since cooperation at the ASEAN-level on maritime gray zone challenges would likely be very difficult, cooperation between and among relevant countries in the region could be an alternative. For instance, the Philippines and Viet Nam, under the two countries’ Plan of Action (POA) for the Implementation of the Strategic Partnership for 2019-2024, has agreed to, among others, cooperate on “capacity-building activities through the exchange of intelligence, military and law enforcement personnel for training and education,”[ii] as well as to “establish practical cooperation and strengthen the sharing of best practices in naval and maritime defense and law enforcement among relevant institutions.”[iii] Addressing/managing maritime gray zone coercion tactics could be an area in implementing these provisions in the POA. Both countries could also jointly call out China’s gray zone coercion activities in the SCS, as they have expressed support to each other when they were at the receiving end of Beijing’s maritime assertiveness.

Building capacity on how to address/manage gray zone challenges could likewise be an area of cooperation with the Philippines’ ally, the United States, and other security partners, such as Australia and Japan. Minilateral cooperation among like-minded countries in the region could also be explored in confronting gray zone challenges.


This paper explored the ways in which ASEAN could play a role vis-à-vis maritime gray zone challenges. However, it is highly unlikely that such security challenges would be part of ASEAN’s agenda. The divergent security interests and perceptions among ASEAN states would make achieving a unanimity-based consensus very challenging. Hence, ASEAN’s role will be limited in implementing and evaluating relevant defense diplomacy initiatives. As such, addressing/managing gray zone challenges will largely be dependent on the individual states’ concerned, as well as bilateral/minilateral cooperation among states outside the purview of ASEAN.

Mico A. Galang is a Defense Research Officer II at the Research and Special Studies Division of the National Defense College of the Philippines (NDCP). For comments and suggestions, please email .


Please scan the QR code to access our Feedback Form for your comments, opinions, and suggestions. Thank you very much and we look forward to hear from you

[i] Christian Vicedo, “China’s PAFMM grey zone maritime challenge to the Philippines,” East Asia Forum, August 13, 2020,

[ii] Philippines-Viet Nam Plan of Action for the Implementation of the Strategic Partnership for 2019-2024, para 7 (a).

[iii] Ibid., para 10.

[i] ADMM, Guidelines for Air Military Encounters, 2018, Singapore: 12th ADMM, 2.

[ii] Ibid., A1-D1.

[iii] ASEAN and the Government of the People’s Republic of China, Declaration on the Conduct of Parties in the South China Sea, 2002, Cambodia: ASEAN, paragraph 10.

[iv] Ian Storey, “Assessing the ASEAN-China Framework for the Code of Conduct for the South China Sea,” Perspective ISEAS-Yusok Ishak Institute, no. 62 (2017): 2.

[v] Carlyle Thayer, “Regional Security and Defense Diplomacy,” ASEAN Security Paper Series, no. 1 (2019): 9.

[vi] Ibid., 9.

[vii] Ibid., 11.

[viii]Robert Delaney, “Philippines’ Teodoro Locsin says Beijing’s South China Sea code is like ‘a manual for feeding a dragon in your living room,’” South China Morning Post, September 25, 2019

[ix] Teodoro Locsin Jr, “Statement of Foreign Affairs Secretary Teodoro l. Locsin, Jr. On the ASEAN-G7 Foreign and Development Ministers Meeting (Session 2),” Philippine Department of Foreign Affairs, December 12, 202,

[i] ADMM, Concept Paper on The Guidelines for Maritime Interaction, 2017, the Philippines: 11th ADMM, 1.

[ii] Ibid., 2.

[iii] Ibid., 2.

[iv] Ibid., 3.

[v] Ibid., 3.

[i] Carlyle A. Thayer, “The Southeast Asia Claimant States, ASEAN and the South China Sea Dispute,” Maritime Issues, November 14, 2016,

[ii] Prak Chan Thul and Stuart Grudgings, “SE Asia meeting in disarray over sea dispute with China,” Reuters, July 13, 2012, (accessed May 6, 2019).

[iii] Bilahari Kausikan, “IPS-Nathan Lectures ‘Dealing with an Ambiguous World Lecture III: ASEAN & US-China Competition in Southeast Asia,’” Lee Kuan Yew School of Public Policy, March 30, 2016,  (accessed May 6, 2019).

[iv] Carolina G. Hernandez, The ASEAN Community Beyond 2015 (Kuala Lumpur: Institute for Strategic and International Studies Malaysia, 2016), 6.

[v] Ibid., 128.

[vi] Hoang Thi Ha, “Taking Baby Steps in the South China Sea,” ISEAS Yusok Ishak Institute Commentary, 58 (2016).

[vii] Barry Desker, “ASEAN Integration Remains an Illusion,’ RSIS Commentary, no. 046 (2015): 1.

[viii]Rozanna Latiff, et al., “Tradition vs credibility: Inside the SE Asian meet that snubbed Myanmar,” Reuters, October 19, 2021,

[ix] ADMM, Concept Paper on Establishing a Direct Communications Link in the ADMM Process, 2017, Nay Pyi Taw, Myanmar: 8th ADMM, 2.

[x] ADMM, Concept Paper on The Expansion of the ASEAN Direct Communications Infrastructure in the ADMM-Plus Countries, 2019, Thailand: 13th ADMM.

[i] Ibid., 29-34.

[ii] Hal Brands, “Paradoxes of the Gray Zone,” Foreign Policy Research Institute, February 5, 2016,

[iii] Ibid.

[iv] Ibid.

[v] Ibid.

[vi] Ibid.

[vii] James Holmes, & Toshi Yoshihara, “Five Shades of Chinese Gray-Zone Strategy,” The National Interest, May 2, 2017,

[viii] This is with reference to either or both the Spratlys and Paracels in the SCS.

[ix] Permanent Mission of the Socialist Republic of Viet Nam to the United Nations  Note Verbale No. 22/HC-2020 dated March 30, 2020.

[i] Michael Green, et. al, Countering Coercion in Maritime Asia: The Theory and Practice of Gray Zone Deterrence (Washington, DC: Center for Strategic and International Studies, 2017), 21.

[ii] Kathleen Hicks, et. al., By Other Means: Part I: Campaigning in the Gray Zone (Washington, DC: Center for Strategic and International Studies, 2019), 7.