Amphibious Assault is Over

The United States Marine Corps (USMC) 2016 Operating Concept identified that ‘[p]eer and near-peer state adversaries have and will continue to refine sophisticated anti-access/area denial (A2AD) capabilities that threaten our strategic reach and operational freedom of maneuver.’ Anti-ship missiles, precise long-range fires, smart mines and pervasive ISR make the prospect of assaulting a hostile shore today more daunting than ever.

The RAND corporation has run simulations which suggest that it would take a salvo of around 50 missiles to knock out a dozen amphibious warfare ships attempting to cross the relatively narrow Taiwan Strait. The threats only get worse as ships get closer to the shore. It is estimated that it would take a modest 10,000 to 20,000 pounds of ordinance to decimate an amphibious landing force of around 90 ships in a hostile littoral.

In response the USMC has acknowledged the need for a ‘paradigm shift and the reinvigoration of a unified naval approach that effectively integrates sea control and maritime power projection capabilities’. The USMC’s answer – still being refined – is Expeditionary Advanced Base Operations (EABO). Rather than being supported by the US Navy at sea, the Marines instead provide crucial support to the US Navy in securing sea control, and, thereby, access to denied waters.

This Concept of Operations (CONOPS) makes the USMC’s determination to replace their Assault Amphibious Vehicle (AAV) with the BAE Systems Amphibious Combat Vehicle (ACV), somewhat perplexing. The idea of an armoured vehicle, carrying Marines from ship to shore, and supporting their assault up a beach, is hardwired into the USMC identity, conjuring memories of hard-fought victories against Japan. But such operations today are hard to imagine ever taking place.

The requirement for the USMC is for the ACV to be able to swim 12 miles to the beach at 8 knots. Meanwhile anti-ship cruise missiles – from China’s YJ-12 to Russia’s KH-35 – have a strike range of approximately 250 miles. The notion that an assault ship could come within 12 miles of a hostile shore is therefore doubtful. Even supposing that the assault ship were able to do so, the journey from ship to shore would be far more perilous than during Operation Overlord. The array of guided anti-tank missiles, smart mines, and kamikaze UAVs that would – with considerable accuracy – sink ACVs during their hour and a half journey to land would be devastating.

USMC Command has recognised this problem, and is, as a Congressional Research Paper noted, ‘exploring ways to create temporary “bubbles” where Marines can get ashore’. The notion of a temporary landing zone, given an enemy’s ability to strike shipping from a considerable distance inland, raises serious doubts as to the security of supply for Marines ashore. The capacity of Marines to push inland must depend on the security of their logistical support, and on the landing of heavier non-amphibious platforms such as the Light Armoured Vehicle-25 (LAV-25) and the M1A1 Abrams Main Battle Tank (MBT), which the ACV is required to be able to support. Landing these systems necessitates a secure shoreline where Landing Craft, Air Cushioned (LCAC) could be deployed. Nor does utilising ACVs in dispersed formations as part of a raiding force seem likely given that helicopters and short take-off, vertical landing (STOVL) aircraft aboard light carriers are better suited to this role.

In the Pacific theatre meanwhile the EABO CONOPS does not require opposed landings for theatre entry. Instead EABO would involve the progressive occupation of small unoccupied atolls, roughly perpendicular to hostile defence lines, to establish spheres of denial using land-based missile systems and long-range artillery. The Marines would have two responsibilities under these CONOPS. Firstly, they would secure lines of supply to the US Navy by denying access to the enemy. Secondly, their ability to project fires onto hostile territory would enable the suppression of hostile A2AD systems, allowing the navy to contest sea control. Since landings on uncontested atolls would not be opposed, there is no requirement for USMC Mechanized Infantry Vehicles (MIVs) to be amphibious.

In the context of the European theatre the proliferation of zones of denial, means that landings would need to take place some distance from the fighting. The long-range mobility of Marine formations would be important in constraining the time and space with which Russia could prosecute offensive operations. Beyond simple mileage, were the Marines to adopt an MIV in line with European allies or US Army colleagues, it would significantly simplify the availability of spare parts, and lighten the logistical burden, while enhancing interoperability.

The cost of having an amphibious MIV is range on land, which limits the capacity for USMC formations to exploit an unopposed landing or perform rapid self-deployment in Europe. BAE claims that the ACV has an operational range of 325 miles and can reach speeds of 65 miles per hour. This is respectable, but is far surpassed by dedicated MIVs such as Rheinmetall’s Boxer, with a range of 684 miles.

The desire to maintain a capacity for amphibious assault arguably stems from the USMC’s concerns that its specialisms will be eroded over time. It is important to note however that while the Falklands War demonstrated no particular need for an amphibious assault vehicle, the British war effort depended on the operational expertise of the Royal Marines. As one Marine observed in the wake of the disaster at Fitzroy, ‘amphibious warfare is not a battle on the North European plain’. Certainly the ingenuity of EABO shows that the Marines have much to offer to complement the US Army’s Multi-Domain Operations. It seems unfortunate therefore that while the USMC is developing concepts to address an evolving threat landscape, their procurement is held captive by bureaucratic and tradition-laden inertia.

Given the scepticism regarding their utility and concurrent budgetary constrains facing the Marines, it is likely that securing the funds needed for procuring a sufficient number of Osprey helicopters, and adapting launchers such as the HIMARS to an anti-ship role, will be difficult. An atavistic insistence on building capabilities geared towards the now infeasible amphibious landing operations of the past will not only divert much needed funds, it will feed the very premise that animates political scepticism regarding the Marines’ utility by presenting the corps as a force built for battlefields that no longer exist.

Instead, if the USMC wishes to project power against hostile shores, it would do well to reconceptualise its role as one of raiding to secure forward support positions as part of a joint fight. Offshore islands, lillypad bases and sea-based assets would allow the Marines to leverage the increasing range of platforms such as UAVs and multi-mission launchers that can be operated from these dispersed sites.

Jack Watling is Research Fellow for Land Warfare at RUSI.

Sidharth Kaushal is Research Fellow for Sea Power at RUSI.