After a false start 15 years ago, the annual Malabar naval exercise has become a key strategic development for the Quadrilateral Security Dialogue partners, the United States, India, Japan and Australia.

Warships from the four nations have just concluded the 26th iteration of Exercise Malabar ^[1], which began under an agreement between the Indian hosts and the US in 1992. The original aim was to improve interoperability between the US and Indian navies, and for many years the exercise involved few ships.

In 2007, warships from the US, India, Japan and Australia took part, but that aroused anger in Beijing, which sent each of the four countries a diplomatic note ^[2], or démarche, criticising what it saw as a developing security relationship.

Australia didn’t take part in the Malabar exercise again until 2020.

Malabar’s expansion reflects the growing ties among the Quad navies. The Quad’s announcement of the Indo-Pacific Partnership for Maritime Domain Awareness ^[3] is another welcome step, but more is needed to formalise a Quad maritime security arrangement. The new partnership is useful because it will give regional nations access to satellite tracking data to monitor ships and enable a common operating picture. However, it needs to be complemented by an initiative that clearly outlines areas of maritime responsibility in the event of conflict in the Taiwan Strait or elsewhere. An updated Radford–Collins arrangement involving India and Japan as partners offers a potential solution.

Named after the then commander-in-chief of the US Pacific Fleet, Admiral Arthur Radford ^[4], and Australia’s then chief of naval staff, Rear Admiral John Collins ^[5], who negotiated it, the Radford–Collins agreement ^[6] was reached in 1951 to establish clear areas of maritime responsibility between the US and Australian navies in the event of war. The agreement also divided up responsibility for ensuring the free flow of maritime trade. The zones were based on the Southwest Pacific and the Anglo–New Zealand–Australian–Malaya, or ANZAM, area, which stretched from the eastern Indian Ocean to New Zealand and across the Southern Ocean to the New Guinea area from south to north. Radford–Collins remains a useful tool for coordinating areas of maritime influence ^[7], but new challenges and partners necessitate an update of the arrangement.

While Radford–Collins was signed during an era that shared some similarities with the current period, the emergence of China as a major maritime force and the evolving Sino-Russia axis has altered the balance of power in the region. The continued growth of the Peoples Liberation Army Navy’s surface and submarine fleets and long-range hypersonic missiles ^[8] will make defending maritime trade more difficult in war time. Beijing’s ongoing use of aggressive maritime grey-zone tactics ^[9] in the South China Sea signals a willingness to use naval power to achieve its geostrategic goals.

The PLA Navy currently has 355 platforms ^[10], including aircraft carriers, surface combatants and long-range submarines. While it is likely to initially concentrate most of its forces in the first island chain close to the Chinese mainland, it would be capable of attacking shipping lanes with long-range missiles or submarines. Any significant interruption to Australia’s supply chains and exports would have devastating consequences. The potential effects of a maritime blockade are highlighted by the disastrous economic impacts of Russia’s blockade of Ukraine ^[11]. Maritime coordination with Indian and Japanese forces alongside the US will be required to help defend the Indo-Pacific shipping lanes should they be threatened.

The recent increase in the naval presence of the UK and France in the Indo-Pacific is, to a large degree, intended to protect regional shipping lanes in the face of increased Chinese grey-zone activities in the South China Sea. Consequently, the Five Power Defence Arrangements ^[12] may bring renewed importance and relevance to Radford–Collins. The FPDA has also remained useful in encouraging multilateral naval exercises, as has the Quad.

The development the Quad ^[13] is a welcome step in the protection of the global rules-based order. All four powers are committed to ensuring freedom of navigation through international waters and that commerce flows are free from coercive forces. It remains a strategic forum, but the Quad has also been useful in encouraging greater partner cooperation as highlighted by the Malabar exercises.

Despite improved collaboration, the Quad partners are spread across two large oceans and have divergent views on some security issues. This includes some Indian divisions over the long-term implications of AUKUS ^[14]. However, major Indian defence think tanks have produced ^[15] mostly favourable pieces on AUKUS, as have Japanese think tanks. While there are some national differences, there’s a joint commitment within the Quad to protect the global rules-based order, and a multilateral Radford–Collins agreement could support its mission. Ultimately, the Quad offers an opportunity for regular joint ‘naval cooperation and guidance for shipping’ operations ^[16], which can help boost cooperation in protecting the merchant marine.

The Australian and US navies are already regular participants in multilateral merchant marine protection exercises like the Bell Buoy series ^[17]. There are also useful international forums like the Pacific Indian Ocean Shipping Working Group. ^[18] Japan and India do not participate in the Bell Buoy exercises or the working group.

The increased importance of the Malabar exercise and the Quad’s establishment of the Indo-Pacific Partnership for Maritime Domain Awareness signal a clear desire to collaborate in the defence of regional shipping lanes against the possibility of Chinese aggression. Radford–Collins was created to establish lines of maritime responsibility, cooperation and communication in the face of a common threat. By formulating a modernised, Quad version of the agreement, the partners can clearly delineate areas of maritime responsibility and formalise common naval communications and procedures in the event of war. Ultimately, a new Radford–Collins agreement would help Australia and its allies refine their joint administrative, capability and operational planning in the Indo-Pacific, bringing a degree of certainty during such uncertain times.