The Treaty of Amity and Cooperation in Southeast Asia (TAC), signed on 24 February 1976 in Bali, Indonesia, marks a pivotal milestone in ASEAN's institutional and diplomatic evolution.

It is not merely a treaty, but a living embodiment of ASEAN’s normative framework -anchored in peaceful coexistence, mutual respect, and non-interference – that has enabled the Association of Southeast Asian Nations (ASEAN) to navigate shifting geopolitical currents for nearly five decades.

Historical genesis of the TAC

The TAC emerged against the backdrop of Cold War tensions, following the Fall of Saigon in 1975 and the retrenchment of the United States from Southeast Asia.

In the face of growing uncertainty, the founding ASEAN members – Indonesia, Malaysia, Thailand, the Philippines and Singapore – convened the first ASEAN Summit in Bali in 1976, where they adopted the TAC as a formal, legally binding expression of regional solidarity.

More than just a peace pact, the TAC laid the foundation for what came to be known as the "ASEAN Way" – a diplomatic culture rooted in quiet diplomacy, non-confrontation, and consensus.

Its principles reflect ASEAN’s unique context: a region of remarkable political, cultural and economic diversity, home to monarchies, democracies, socialist republics and military regimes, all of which must coexist without igniting regional conflict.

The core principles of the TAC

The TAC is founded upon the principles articulated in its Preamble and codified in Article 2. These are:

(1) Mutual respect for the independence, sovereignty, equality, territorial integrity and national identity of all nations;

(2) The right of every State to lead its national existence free from external interference or coercion;

(3) Non-interference in the internal affairs of one another;

(4) Settlement of disputes by peaceful means;

(5) Renunciation of the threat or use of force; and

(6) Effective cooperation among states.

These principles remain central to ASEAN’s external relations, regional cooperation and conflict resolution mechanisms.

They are reinforced by institutional structures such as the High Council, established under Chapter IV of the TAC, designed to mediate disputes through good offices, inquiry or conciliation.

ASEAN’s organisational culture and the ‘ASEAN Way’

The TAC exemplifies ASEAN’s intergovernmental character and aversion to legalism.

Disputes are preferably resolved behind closed doors, with leaders resorting to quiet diplomacy, informal consultations and personal rapport.

As such, while the TAC envisions dispute settlement mechanisms, these are rarely invoked formally.

ASEAN relies instead on senior-level diplomacy, consensus and mutual accommodation.

The TAC’s structure allows ASEAN to function effectively without a supranational authority.

This is especially crucial for a region with stark developmental disparities and divergent political systems.

The TAC thus acts as a stabilising force, enabling cooperative integration without the necessity of uniformity or political convergence.

Evolution and Expansion of the TAC

Initially limited to Southeast Asian states, the TAC has since undergone three amendments – in 1987, 1998 and 2010 – expanding eligibility for accession to states outside the region and to regional organisations composed of sovereign states.

The Treaty was first opened to non-ASEAN states in 1989, beginning with Papua New Guinea.

Since then, the TAC has grown into a globally embraced framework.

Before this, 55 states and entities had acceded to the Treaty and today Uruguay and Algeria became the 56th and 57th High Contracting Parties respectively.

This expansion reflects a growing recognition of the TAC’s values and ASEAN’s rising profile as a convening power in global diplomacy.

Countries wishing to participate in ASEAN’s multilateral platforms – such as the ASEAN Regional Forum (ARF), East Asia Summit (EAS), and ASEAN+3 – are often required to accede to the TAC as a prerequisite, reinforcing its central role in regional and inter-regional engagement.

Why countries outside ASEAN are joining the TAC

The global resonance of the TAC lies in its flexibility, neutrality and the universality of its principles.

As Wisma Putra Secretary-General Datuk Seri Amran Mohamed Zin recently noted, more countries are now seeking to accede to the TAC as a means of opening the door to deeper cooperation with ASEAN.

The Treaty offers a diplomatic “gateway” for peaceful engagement and mutual development – particularly attractive in an era marked by great-power rivalry and geopolitical fragmentation.

Accession to the TAC signals a country’s commitment to the ASEAN ethos: peaceful coexistence, non-alignment, and a preference for multilateral dialogue over confrontation.

In the words of Malaysia’s Foreign Minister, Dato’ Seri Utama Mohamad Hasan, Algeria and Uruguay’s accessions reflect their “firm commitment to these principles” and their desire to “foster dialogue, mutual respect, and peaceful coexistence in an increasingly complex and interconnected world”.

Procedure for accession

The process of accession is deliberate and inclusive.

Interested countries submit their request to the ASEAN Senior Officials’ Meeting (SOM), which evaluates their readiness and political commitment.

Recommendations are then forwarded to the ASEAN Foreign Ministers’ Meeting (AMM) for final decision.

The accession culminates in the formal signing of the Instrument of Accession, as witnessed during this 58th AMM in Kuala Lumpur.

This procedural rigour ensures that new signatories genuinely share ASEAN’s foundational values and enhances the legitimacy of the TAC as a global diplomatic instrument.

The 2025 milestone: Algeria and Uruguay join the TAC

The accessions of Algeria and Uruguay mark a significant moment in the TAC’s journey.

Algeria represents North Africa, while Uruguay hails from Latin America – two regions historically distant from ASEAN’s immediate geographical orbit.

Their inclusion signifies the growing appeal of ASEAN’s model of peaceful diplomacy.

In his remarks at the signing ceremony, Dato’ Seri Utama Mohamad Hasan highlighted how this event deepens ASEAN’s linkages with “regions that share our aspiration for peace, prosperity, and sustainable development”.

It illustrates ASEAN’s capacity to bridge continents and ideologies through shared commitment to the rule of law and peaceful coexistence.

With 57 members now under the TAC umbrella, the treaty has become a symbol of multilateral consensus in a fragmented world.

It is one of the few intergovernmental frameworks where the Global North and South, liberal democracies and authoritarian regimes, and large and small states coexist under a common code of diplomatic conduct.

The TAC in a fragmenting world

The TAC’s endurance is a testament to ASEAN’s pragmatic diplomacy and soft institutionalism.

It has allowed ASEAN to transform from a Cold War security alliance into a mature and outward-looking community.

It has also helped ASEAN maintain a semblance of neutrality amidst great power rivalries, from the Cold War to today’s multipolar order.

In an age when many multilateral structures are under strain, the TAC offers a unique model – non-binding in enforcement, yet binding in principle; slow in process, yet steady in delivery.

It provides an inclusive, ideologically neutral framework for engagement – attractive to countries from every continent seeking peace and partnership in the Indo-Pacific century.

As the accession of Algeria and Uruguay has shown, the spirit of Bali 1976 continues to resonate far beyond Southeast Asia.

TAC is no longer just ASEAN’s diplomatic pillar but it is now one of the world’s most quietly successful instruments of peace.

-- BERNAMA

Dr Kamarul Zaman Yusoff is a Senior Lecturer at the College of Law, Government and International Studies, Universiti Utara Malaysia.