The maritime strategic balance in the Indo-Pacific is changing rapidly. The future of undersea nuclear deterrent forces has strategic, operational and force structure aspects for all major powers in the region. Strategic competition in an increasingly competitive environment has a significant maritime element, which itself is profoundly influenced by the continuing importance—and progressive expansion—of the region’s underwater nuclear deterrent forces.

To a greater extent than during the Cold War, both threatening and protecting such assets will be difficult to separate from other maritime campaigns. This particularly applies to potential anti-submarine warfare (ASW) operations in the East and South China Seas, as well as to India and Pakistan and to North Korea, creating uncertainty over the possibility of unplanned escalations and outright accidents.

Maintaining any kind of regional balance will, therefore, call for cool judgements on the part of all the players, judgements that will need to be continually revised in the light of technological innovation and force development.

The US Navy’s nuclear-powered ballistic missile submarine (SSBN) force is central to the country’s nuclear arsenal. While the navy can’t be complacent about threats to the survivability of its submarines, until there are revolutionary developments in sensor technology, the combination of geography, oceanography, and platform and missile capabilities means that its at-sea deterrent will remain the most secure element of America’s nuclear force and thus receive high priority in funding.

The problem for the US Navy is that it will need to start replacing the Ohio class within the next decade, but the cost of 12 new Columbia-class submarines will severely limit its ability to regenerate all the other force elements that will be required to meet the combined challenges of China and Russia.

The navy’s efforts represent just one part of a strategy to push the US’s competitors off balance and regain the strategic initiative. An important maritime element is likely to be undermining China’s efforts to create an underwater ‘bastion’. Here, the Americans must weigh the benefits of actively threatening the security of the People’s Liberation Army Navy’s SSBN force against the resource commitments that that would entail, as well as the complications that it could represent for alliance arrangements, notably with Japan and Australia.

In seeking to become the predominant maritime power in the western Pacific, China has its own problems of resources and technology. However attractive the concept of an at-sea deterrent force within its nuclear inventory may be, China must first extend the range of its submarine-launched missiles and considerably improve the stealth qualities of its missile submarines if it is to create a capability sufficient to pose a credible threat to the continental United States.

Russia’s challenges are in some ways parallel to those of the US, particularly its need to sustain an SSBN force while modernising the remainder of its navy. Maintaining an at-sea nuclear deterrent remains the highest priority. However, replacement of the older SSBN with the new Borey class must be consuming a very large share of the Russian navy’s resources. To the SSBN program must be added the need to renew the nuclear-powered attack submarine force and continue development of the ASW capabilities necessary to secure the bastions against potential attackers. The limited money available means that Russia’s maritime power-projection assets don’t enjoy the same level of attention.

Japan’s defence expansion, despite the tensions with China and the rise of the PLA Navy, has been relatively limited. Its most significant new elements are focused on developing amphibious forces capable of responding rapidly to any threat to the Ryukyu Islands, including the contested Senkaku (Diaoyu) Islands. Japan’s ASW efforts are much less visible in, but perhaps more significant for, its maritime strategy. Japan’s submarine force is slowly expanding, and the modernisation of its surface and air ASW forces continues.

Australia faces equivalent challenges. Because it is one of the few regional players with substantial high-technology capabilities, particularly in the ASW domain, Australia’s assistance will be eagerly sought by the Americans, just as they have long looked to Japan. While its defence expansion remains relatively constrained—and slow—Australia’s emerging force structure will provide both independent national capabilities and strategic weight in alliance terms in ways that are relatively new. Australia has been a regular presence in the South China Sea over many years, but the latest Indo-Pacific Endeavour task group deployments have been on a larger scale than the individual ship deployments of the recent past.

North Korea remains a wild card. Its efforts to develop an underwater nuclear deterrent are only a small part of the increasingly complex problem its future presents for neighbouring countries and the region as a whole.

India must balance its apparently unresolvable tensions with Pakistan against a developing strategic rivalry with China that has important maritime dimensions. The growing Chinese economic and military presence in the Indian Ocean threatens India’s self-image as the dominant power in the region. India’s interest in the South China Sea represents something of a riposte and a deliberate effort to complicate China’s maritime strategy.

On the other hand, the entry of the first Indian SSBN into operational service and the start of its deterrent patrols may have added to India’s nuclear capabilities, but they also create a hostage to fortune that the Indian Navy must factor into its dispositions. Whether Pakistan will add to India’s problems by embarking nuclear weapons in its submarine force is uncertain, as is the priority that the Pakistan Navy will give to locating and tracking Indian SSBNs.

In sum, strategic competition in the increasingly competitive Indo-Pacific has a significant maritime element. Distinguishing threatening and protecting nuclear assets from routine maritime campaigns is increasingly difficult. As SSBN capabilities proliferate, and ASW technology advances, maintaining a regional maritime balance will increase in complexity.

This piece was produced as part of the Indo-Pacific Strategy: Undersea Deterrence Project ^[1], undertaken by the ANU National Security College ^[2]. This article is a shortened version of chapter 2, ‘Maritime and naval power in the Indo-Pacific’ ^[3], as published in the 2020 edited volume The future of the undersea deterrent: a global survey ^[4]. Support for this project was provided by a grant from Carnegie Corporation of New York.