Indonesian President Prabowo Subianto, right, and Australian Prime Minister Anthony Albanese after signing a cooperation agreement document at the Merdeka Palace in Jakarta on 6 February 2026 (Bay Ismoyo/AFP via Getty Images)

Indonesia–Australia Security Treaty: Middle powers choosing consultation over blocs

Regional states are furthering security ties to retain autonomy, not to balance a single adversary.

Emirza Adi Syailendra

16 February 20264 min read

Leaders of Indonesia and Australia have framed the Jakarta Treaty 2026 as a response to “challenging times”. They refer to a more volatile regional environment, amid intensifying major-power competition, evolving US and Chinese defence postures, and anxieties about overdependence or exposure to great‑power coercion. The treaty is thus less about balancing a single adversary than about institutionalising consultation and cooperation mechanisms that safeguard decision‑making autonomy in a contested Asia‑Pacific, including commitments to consult in the event of a threat and to deepen security coordination.

This logic aligns with broader shifts in middle‑power strategy. At the 2026 World Economic Forum in Davos, Canadian Prime Minister Mark Carney warned that the “old order is not coming back” and argued that “middle powers must act together, because if we’re not at the table, we’re on the menu,” linking this to the need for greater strategic autonomy in energy, critical minerals, finance, and supply chains. Carney’s remarks encapsulate a wider impulse among secondary states to manage systemic volatility collectively, without being fully absorbed into rigid bloc politics.

In the works long before Carney’s observations, Australia–Indonesia cooperation reflects this dynamic: the treaty elevates the relationship “to a new level,” codifying habits of consultation, interoperability, and crisis coordination, and creating practical instruments that widen operational and strategic manoeuvre while preserving national control over the use of force. The outcome reinforces the central argument I made in The Interpreter last year when the treaty was first flagged.

Viewed through this prism, the Indonesia–Australia security treaty functions as a key pillar in the Australia’s vision of emerging agency‑preservation architecture – a structured network of treaties, partnerships, and cooperative mechanisms that shape an Indo‑Pacific in which middle powers aspire to retain strategic choice and autonomy. As Foreign Minister Penny Wong put it in her 17 November 2025 keynote address at the Australian Institute of International Affairs, Australia and its partners are not “just residents” of the region but architects building its future through landmark agreements, enhanced partnerships, and collective engagement with neighbours and multilateral institutions. Wong invoked the metaphor of architecture to describe how Australia has worked with countries across ASEAN, the Pacific Islands Forum, and beyond to build inclusive infrastructure, shared capacity for defence and security, and norms that uphold sovereignty and stability in an increasingly contested environment that normalise the use of brute force.

Under this framing, the Australia–Indonesia treaty’s “operational levers” – codified consultation, coordination frameworks, and capacity‑building initiatives – are designed to expand room for manoeuvre for middle powers. By embedding cooperative security practices within the contours of this agency‑preservation architecture, the treaty illustrates how middle powers are reshaping the regional order as an alternative to hegemonic hierarchies.

Calibrated policy choices expand operational space.

The language of agency preservation resonates even in a nation long defined by its self‑imposed constitutional restraint: Japan. At a post‑election news conference on 9 February, Prime Minister Sanae Takaichi stated Japan must demonstrate the resolve to defend itself: “No one will come to the aid of a nation that lacks the resolve to defend itself with its own hands.” Takaichi has accelerated defence spending to record levels and brought forward a comprehensive security strategy review, justified by warnings about a potential “three‑front contingency” involving China, Russia, and North Korea. Her government links this military build‑up to economic security measures and to a broader push for what Japanese officials describe as more robust “collective deterrence” alongside the United States, positioning greater self‑reliance as necessary to sustain alliance credibility rather than to dilute it. Here, agency preservation is operationalised through enhanced capabilities and resilience: Tokyo seeks to increase its capacity to shape regional outcomes and share burdens within the alliance, thereby reducing vulnerability to both abandonment and entrapment.

In South Korea, debates over “strategic autonomy” illustrate a related pattern of desired for limited autonomy under the alliance framework. Recent US guidance, including the new National Defence Strategy, signals expectations that Seoul “take the lead in deterring North Korea” while Washington reallocates resources toward China, prompting domestic discussions on balancing alliance dependence with flexibility toward China and other regional options. A notable milestone came in late 2025, when South Korea secured US support for conventionally armed, nuclear-powered submarines, including avenues for fuel supply – sovereign assets designed to enhance deterrence, reduce reliance on US platforms, and provide leverage vis-à-vis China. Yet constraints persist: while polls indicate strong public support for indigenous nuclear weapons, Washington remains opposed to South Korean nuclear armament to uphold non-proliferation and extended deterrence frameworks. Strategic autonomy in Seoul is thus pursued not by rejecting alliance ties, but through calibrated policy choices that expand operational space without undermining the US partnership – a logic that mirrors the Indonesia–Australia approach of consultation, coordination, and agency preservation without forming a fixed balancing coalition.

The Indonesia–Australia treaty represents only one part of a regional trend where middle powers are constructing dense security ties as part of an emerging architecture for preserving strategic agency. In practice, the Jakarta Treaty 2026 strengthens defence coordination, interoperability, training, and crisis consultation, and sits alongside new initiatives such as embedded officers and joint training facilities that deepen shared capacity without merging command structures. Ideationally, it supports a more multipolar and networked regional security architecture, and resists the emergence of coercive hierarchies dominated by any single great power.

Rather than signalling bloc consolidation, these moves show how Asian middle powers actively shape the rules and structures of regional order – retaining strategic independence while collectively hedging against uncertainty and managing the risks of great‑power rivalry.

About the author

Emirza Adi Syailendra

Emirza Syailendra is a Postdoctoral Research Fellow at the Maritime Security Programme, S.

Topics

Indonesia Japan South Korea Australia Defence & security