The re-emergence of great-power competition and a deteriorating strategic environment are forcing the US Army to rethink not just its approach to land warfare but also its future role alongside the US Marine Corps in key regions around the globe. Nowhere is this transformation more apparent and meaningful than in the Indo-Pacific, where the People’s Republic of China poses the most acute challenges.

A new ASPI report, US land power in the Indo-Pacific: opportunities for the Australian Army ^[1], released today, finds that the implementation of the US Army’s multi-domain operations doctrine and reorganisation is driving a greater emphasis on joint exercises and ensuring there are no gaps in defence cooperation among allies and partners in deterring Chinese aggression.

The concept of multi-domain operations is not new. It’s partly an evolution ^[2] of previous conceptual frameworks such as AirLand battle ^[3], full-spectrum operations and unified land operations, requiring the employment of long-range fires and non-kinetic capabilities against enemy air and missile defences. It aims to ensure that US forces can expand the battlespace ^[4] and achieve mission success without an assured ability to dominate in each individual domain.

The codification of the doctrine is designed to position the US Army as the key force ^[5] that joint force commanders need to hold critical terrain, signal America’s commitment to allies and partners, and defeat adversaries in close combat. This shift has advanced the use of multi-domain taskforces to address these functions at scale.

Multi-domain taskforces are an integral part ^[6] of the US Army’s push to build coalitions as a means to complicate China’s decision-making and minimise China’s advantage of compact lines of manoeuvre, communications and logistics. As US Army Secretary Christine Wormuth told ^[7] an audience in Washington in March, the branch intends to commit more combat-credible forces to the region and establish theatre distribution centres in Guam and potentially Australia, Japan and the Philippines. If these efforts are successful, the US Army will be able to support other forces by providing logistical hubs in the region.

US Army Pacific, America’s theatre army for the Indo-Pacific, is contributing ^[8] to concepts for strategic competition with China through two primary campaigning activities. The first involves conducting in-theatre sustainment rehearsals to increase joint readiness and enhance allied and partner capacity to deny human and geographical terrain to an adversary. The second effort involves establishing pre-positioned stocks and leveraging security force assistance brigade operations to test for security cooperation continuity with partner countries that currently don’t host US land forces. These developments hold important insights for key US allies, including Australia and Japan.

Australia’s new unifying strategic approach to national defence and the high degree of convergence this has with US defence strategy offer a timely window of opportunity for the Australian Army to work more closely with US land forces.

The ongoing optimisation ^[9] of the Australian Army for long-range strike, missile defence and littoral lift creates opportunities for deepening the US–Australia alliance in the land domain, particularly as the heightened focus on the immediate region implies that Australia’s land-force contributions will be in archipelagic Southeast Asia and of an increasingly maritime and amphibious quality.

Australia’s defence strategy rightly prioritises national defence ^[10], but this does raise questions about the capacity of an integrated Australian Defence Force to meet the future strategic needs of the alliance. Given that neither the US nor Australia can deter China alone, it’s important that the Australian defence establishment and military leaders consider how a transformed and multi-domain-capable Australian Army should work with US land forces to deter conflict during competition and crisis.

One option is for Australia and the US to investigate ways to jointly employ, deploy and logistically support long-range hypersonic weapon systems in Australia. Expanding on the two nations’ successful cooperation ^[11] on the development and testing of hypersonics would send a purposeful signal to Beijing that Australia possesses a deterrent capability at a range to defend its northern approaches and support US military operations in the South China Sea and East Asia. This would likely instil greater doubt in the minds of China’s military leaders about the attendant risks of aggression and likelihood of a collective response.

Littoral manoeuvre and logistics training is another priority area where the Australian Army could further cooperate with US land forces. Australia’s amphibious force will expand over the next decade with the addition ^[12] of new medium and heavy littoral manoeuvre vessels through Project Land 8710. From 2024, the planned Australian Army littoral lift groups ^[13] will support training and operations in the Northern Territory, northern Queensland and southeast Queensland could benefit from exercising with US marine littoral regiments in simulated expeditionary advance base operations or missions tailored to Australia’s national defence and strategic interests.

Australia’s efforts to build an integrated maritime strategic construct ^[14] could also benefit from increased local training in maritime operations with the Japan Self-Defense Forces and with the new US Army watercraft systems capabilities in our northern approaches. Indeed, the US–Australia–Japan minilateral relationship offers many opportunities for expanded exercises and deployments ^[15] now that the Japan–Australia reciprocal access agreement is in effect.

Most importantly, Washington’s interest in forward-basing more of its strike assets in Australia is now underpinned by a pressing need for the ADF to enact a strategy of denial in our immediate region. Positioning a full US Army brigade combat team equipment set ^[16] in northern Australia, for example, would support both US and Australian national interests and additional actions to deter China from escalating to armed conflict. This avenue might not be a decisive factor in Beijing’s strategic calculus on its own, but it’s a natural fit with Australia’s defence strategy and could bolster the capacity of an integrated ADF to respond in the event of a regional crisis involving the US and China.

Amid increasing uncertainty, it’s paramount that the Australian Army, the US Army and the US Marine Corps expand their patterns of cooperation and prioritise the development of a shared understanding of coalition activity. This work should be mutually reinforcing and constitute part of Australia’s approach to managing risks and threats and balancing its contributions to deterrence in the Indo-Pacific.