The planning guidance ^[1] issued by the new US Marine Corps commandant, General David Berger, is unusually forward-leaning and well written by the standards of most military doctrine. It has received a positive reaction ^[1] in the US and won over sceptics ^[2] because its analysis is radical and persuasive.

The impact is likely to be felt in Australia, as a key US ally and host to a Marine Corps rotational presence. It could also usefully influence local debates on military strategy, joint force design and the changing nature of amphibious warfare.

The guidance includes innovative thinking ^[3] about the manpower model that should be of universal interest to professional militaries. But the most consequential parts concern force design and war-fighting.

Berger ushers in a strategic mission shift, from the marines’ traditional power-projection role to a focus on maritime denial operations and support for the US Navy’s sea control functions. The core assumption underlying this major re-posturing is that America’s ‘ability to project power and influence … is increasingly challenged by long-range precision fires; expanding air, surface, and sub-surface threats; and the continued degradation of our amphibious and auxiliary ship readiness.’

That China, Russia and Iran loom large in this threat assessment is no surprise. But the inertia and complacency that have built up from years of US military operations in ‘permissive environments’ is hard to overstate. The planning guidance cuts through that.

With official statements of doctrine, impact is measured by both message and messenger. Few of the ideas are wholly original, but the guidance carries special weight because it bears the imprimatur of a service chief.

The US national defence strategy ^[4] and national security strategy ^[5] define strategy at the national level. But the planning guidance stands out as the most senior indication yet that the US military (or the Marine Corps at least) is belatedly adjusting to seismic shifts in the balance of power and technological change that have called time on US strategic primacy. This is not a radical document by the iconoclast standards of retired US Marine Corps Colonel T.X. Hammes ^[6]. But as a fundamental shift in thinking, it marks a significant and long-overdue change of direction.

The guidance acknowledges that the status quo underpinning US forward-deployed forces is no longer tenable ‘as our forces currently lack the requisite capabilities to deter our adversaries and persist in a contested space to facilitate sea denial’. It argues for repurposing the marines to ‘create a mutually contested space’ by leveraging geographical ‘positional advantage’ and exploiting military technologies that give the edge to denial operations over classical power projection. The ability of adversaries to field long-range guided weapons that ‘threaten manoeuvre by traditional large-signature naval platforms’ is a two-way street that can be turned to the US’s advantage as a means to deny power projection to others and secure localised sea control.

Such a tectonic shift necessitates closer, back-to-basics integration with the US Navy. This aims to reverse the ‘anomaly’ of the past two decades when the Marine Corps served primarily as a land-based adjunct to the US Army in the Middle East and Afghanistan.

The guidance asks rhetorically what the navy needs from the marines.

‘First and foremost, we must be prepared to be employed as Fleet Marine Forces.’ This looks like a disjuncture from the marines’ recent operational experience, but in broader sweep, the corps is reverting to historical type, as an amphibious force designed to support fleet operations and naval campaigns.

While the guidance is global in scope, III Marine Expeditionary Force ^[7] is identified as the ‘main focus of effort’ to maintain a ‘credible deterrent to adversary aggression in the Pacific’. This heightened emphasis on the Indo-Pacific is underscored by a ‘prioritized focus on China’s One Belt One Road initiative and Chinese malign activities in the East and South China Seas’. Leveraging the strategic advantages of ‘key maritime terrain’ lends itself most obviously to a Pacific geographical setting with regard to the first and second island chains. Maintaining a strategic focus on the Indo-Pacific Command area is easier said than done, but Berger has at least signalled his priorities clearly.

The most refreshing aspect of the guidance is its willingness to shed shibboleths in force design: ‘What served us well yesterday may not today.’ Berger has already jettisoned ^[8] the Marine Corps’ longstanding, almost canonical attachment to a 38-ship requirement. In a nod to a more flexible, distributed and survivable force structure, he eschews fixed numbers and platform preferences and calls for ‘smaller more lethal and risk-worthy platforms’. He comes close to admitting that large, flat-topped amphibious ships are too vulnerable ^[9] to risk in active conflict zones against major adversaries, such as China, however useful they remain in peacetime and low-intensity conflicts.

Like any strategy, the guidance depends partly on the Pentagon’s ability to fund it. Change of this kind cannot happen as long as political dysfunction rules the US defence budget. But implementation costs should not be prohibitively high, especially if the shift in thinking is accompanied by a diplomatic effort to enlist US allies as integral to the new strategy.

The guidance references the possible forward deployment of HIMARS ^[10] batteries armed with long-range anti-ship missiles. The Marine Corps is already equipping itself for a maritime denial role, recently committing to buy Norway’s Naval Strike Missile ^[11]. When the Pentagon deigns to buy foreign weapons, that usually indicates serious intent.

There’s every reason for the navy and its new chief of naval operations, Admiral Mike Gilday, to endorse a new mission set for the Marine Corps that actively supports sea control and subordinates the marines’ role in a maritime strategy. The effect on the US strategic position in the western Pacific could be restorative, and potentially transformational.

What are the implications for Australia and the ADF?

First, the guidance should underline the necessity of leveraging Australia’s surrounding geography to maximise the defensive advantages of archipelagic Southeast Asia and the Southwest Pacific, our own concentric island chains. The ADF could do a lot worse than to adhere to Berger’s injunction to ‘focus on exploiting positional advantage and defending key maritime terrain that enables persistent sea control and denial operations forward’. The same principles apply.

Second, Australia isn’t mentioned in the guidance, but its locational advantages in the kind of strategy outlined by Berger are obvious even though the marines’ current activities in the Northern Territory are training-based.

Third, even more than the marines, the ADF needs ‘risk-worthy platforms’. Too much capability is concentrated in too few platforms. While Berger refers specifically to the future amphibious portion of the US fleet, one line seems equally pertinent to the high-priced procurement habits of Australia’s navy and air force: ‘We must continue to seek the affordable and plentiful at the expense of the exquisite and few’.

Fourth, the fact that the Marine Corps is thinking in such bold terms about its future missions may persuade non-diehard Australian sceptics that amphibious warfare is not obsolete in high-intensity conflicts. Rather, it evolves. ‘Forced entry’ still has its place in amphibious warfare, just as storming the beach is a photogenic staple at exercises like Talisman Sabre ^[12]. But the acme of amphibiosity is more about how to incorporate land, sea and air forces within an overall national maritime strategy.

There are obvious differences in scale and setting between the US Marine Corps and the ADF, but the intellectual framing of the guidance is sufficiently robust as to suggest a transposable model for closer integration of Australia’s army, navy and air force, as well as a realistic footing on which to base future joint operations and planning within the alliance.