As the Department of Defense (DoD) turns its attention to countering and deterring China’s People’s Liberation Army (PLA), mastering amphibious assault seems paramount. Yet, the services are losing their expertise in integrating mobile protected firepower (MPF) into amphibious assaults, and the joint force will be weaker for it.
Having divested itself of its armored forces, the Marine Corps can no longer integrate organic MPF into its amphibious training and operations. If the service needs armor, then–Marine Corps Commandant General David H. Berger said it should look to the Army.1 But the Army is decades out of practice and does not train its armored crewmen for amphibious operations. Its doctrine lacks details on armor integration with amphibious forces, and the Army has no units designated as “amphibious” to test new tactics and equipment.
The Marine Corps and Army’s training priorities, doctrine, and equipment are not aligned with the capabilities DoD expects of them, and this mismatch will prevent the joint force from successfully integrating armor into its amphibious operations. The joint force must remedy this misalignment.
History Of The Modern Amphibious Assault
After the Allied failure at Gallipoli, many believed amphibious assault was obsolete.2 They concluded attempting to take a beachhead against modernized weapons was suicide. This did not deter the U.S. Marine Corps, which analyzed what would be necessary to conduct amphibious operations if the United States went to war with Japan. By 1938, the service had codified its findings in Fleet Training Publication Manual 167: Landing Operations Doctrine, and in 1943, it stood up the Troop Training Unit, Amphibious Training Command, Pacific Fleet, at Camp Elliott.3 There, Marine Corps and Army divisions trained in earnest. Throughout World War II, more amphibious training centers opened, evidence of the critical role amphibious operations played in the conflict.4
Fortified machine-gun nests and bunkers overwatching beachheads led Army and Marine Corps leaders to deem MPF support necessary for infantry to storm beaches. However, the MPF was limited to 37-mm main-gun-equipped light tanks, which lacked the firepower to destroy enemy pillboxes.5 In addition, because the tanks were not amphibious, they were relegated to later waves of the assault. The development of heavier, armed amphibious tanks that could support the initial waves and use their firepower to destroy fortified enemy positions allowed commanders to defend beaches from counterattacks and exploit breakthroughs.6
The combined arms team of infantry and armor, supported by naval fires and aerial bombings, became the linchpin of the United States’ island-hopping campaign in the Pacific.7 Unfortunately, as time passed, the Army closed all its amphibious schoolhouses and focused on the Russian threat in Central Europe during the Cold War. The Marine Corps maintained expertise in amphibious assault but divested its MPF, which brought the joint force to where it stands today.
Doctrine, Training, And Education
DoD Directive 5100.01 tasks the Army and Marine Corps with conducting amphibious operations and gives the Marine Corps “primary responsibility for the development of amphibious doctrine, tactics, techniques, and equipment.”8 Both services have doctrine that describes amphibious operations and the integration of MPF. However, none provides much detail. Joint Publication 3-02: Amphibious Operations says tanks can be used in the first waves of an amphibious assault, add combat power and mobility for the landing force, and require special considerations for embarkation.9 While true, this also lacks detail. Army doctrine should provide it, but its manuals for armored formations do not discuss planning considerations for amphibious assaults.10 In addition, the Army is not currently training its armored crew members in amphibious operations, and it has failed to capitalize on opportunities to do so in exercises with the joint force and multinational partners.
Recently, the Army deployed forces to the Indo-Pacific during Talisman Sabre 23 and Balikatan 2024. In the former, the Army deployed a company of M1A2 Abrams tanks to train with Australian partners. Yet, the training was land-based and did not include amphibious operations.11 Balikatan 2024 saw Army and Marine Corps forces working jointly with the Philippine military to seize islands. During the exercise, the joint force showcased an assortment of capabilities, which included the Marine Corps’ new amphibious combat vehicle (ACV) and littoral reconnaissance teams and the Army’s Multi-Domain Task Force and amphibious assaults.12 Unfortunately, MPF was missing from this exercise, and, thus, integration techniques could not be practiced.
This leaves the schoolhouses to prepare the joint force to integrate MPF into amphibious assault. The obvious incubators are the Marine Corps’ Assault Amphibian School at Camp Pendleton and the Army’s Maneuver Center of Excellence (MCoE) at Fort Moore. The former runs five courses that educate and train Marines on amphibious assault—from instructing crews on operating mechanized vehicles in littoral environments to educating officers on planning considerations.13 Unfortunately, the course does not incorporate MPF or admit Army armor crews.
While the MCoE educates service members on the principles of MPF integration, it does not teach amphibious assault. Its Captains Career Course, for example, teaches MPF integration from the company to the brigade level.14 Recently, the course has turned its attention to the Indo-Pacific, including the employment of MPF in the region. However, its scenarios exclude amphibious assault. They center on the Korean Peninsula, with units already established there.15
These shortcomings do not bode well if the joint force suddenly requires armored units to participate in amphibious assaults, as planners will not have been educated on the principles of these operations. When combined with the shortfalls in training and doctrine, the lack of preparedness is evident.
Equipment Shortfalls
The lack of proper equipment is another issue. To conduct MPF-integrated amphibious assaults, the joint force needs a fleet of connectors or landing ships capable of providing ship-to-shore mobility and logistical support. It also needs a properly amphibious MPF capable of being deployed in the first wave to support infantry units against an enemy’s fortified positions.
The Marine Corps’ move to become a leaner force has meant smaller connectors, which would be unable to support MPF logistically in an amphibious operation. Current connectors do not have the same capacity or capabilities as the military’s legacy tank landing ships (LSTs). While the Army’s logistical support vessel (LSV) can transport up to 15 M1A2 Abrams tanks, its maximum speed of 12.5 knots fully loaded is short of that required for survivability.16 Consequently, combatant commanders may be denied MPF integration or have to risk their combat power being destroyed before it can land.
The next hurdle is the lack of amphibious MPF. During Balikatan 2024, the Marine Corps’ ACV demonstrated its ability to conduct an amphibious assault.17 However, although the ACV is armored, it does not meet the definition of MPF. The ACV can be mounted with a remote-operated heavy machine gun or 40-mm automatic grenade launcher, neither of which can neutralize reinforced bunkers and armored vehicles. The ACV’s armor rating is classified, but if it is similar to that of the Army’s Stryker, it can protect against only up to 14.5-mm armor-piercing ammunition. A variant with a 30-mm cannon is in development, but one of the lessons of World War II amphibious assaults is that even 37-mm ammunition is not sufficient to defeat bunkers.18
If the ACV cannot provide enough MPF, the Marine Corps must use the Army’s tanks to fill the role. Marines have used the M1A2 in the past, so it seems the obvious choice. However, the Abrams’ more than 74-ton weight limits its ability to be deployed en masse and the locations for deployment. In addition, the Abrams is not amphibious. It can be fitted with deep-water wading kits that allow it to ford water up to six feet, but it would not be able to launch as far out as the ACV.19 This means it could not lead the lighter armored vehicles on the initial wave and perform its intended purpose as MPF.
This leaves the Army’s M10 Booker. Designed to support infantry, the Booker is half the weight of the Abrams. The Army identified a requirement for MPF support for its airborne units when seizing airfields as part of a joint forcible entry (JFE).20 The joint force defines seizing a beachhead as JFE, so it stands to reason that if the Army provides MPF for an amphibious assault, it will look to the M10 to fill that role.21 Unfortunately, the M10 also is not amphibious and lacks a deep-water wading kit. It must be delivered directly onto the beach. This lack of MPF designed for amphibious assault will handicap these operations.
Can The Postmodern Amphibious Assault Defeat The PLA?
Not all in the joint force see MPF as a requirement for amphibious operations. The units sent to Balikatan 2024 suggest the joint force’s priorities for the Indo-Pacific theater. The Army sent the 25th Infantry Division, which focused on conducting air assault operations with partners.22 The Army’s contribution to taking islands was its Multi-Domain Task Force equipped with the high-mobility artillery rocket system (HIMARS), not its armored forces. Meanwhile, the Marine Corps focused on its littoral reconnaissance team concept to provide sensing for the Army’s task force and the Marines’ organic fire capabilities.23 This aligns with how then–Lieutenant General Eric Smith described the Marine Corps’ new vision in which Marines use long-range precision fires for “killing armor at ranges . . . about 15, 20 times the range that a main battle tank can kill another main battle tank.”24
The joint force’s priorities indicate it has moved past the modern amphibious assault to the postmodern, in which small, distributed teams will conduct exquisite targeting to destroy enemy positions and armor to enable lightly armored infantry to seize the beachhead.
While this method of amphibious assault is the cutting-edge type of fighting the United States prefers, it is not sustainable. China has invested in its Marine Corps (PLANMC) to integrate MPF into its amphibious assaults. It also maintains amphibious combined arms brigades in its army (PLAGF). These amphibious combined arms battalions could be used to seize beachheads in Taiwan, with ZTD-05 amphibious tanks and their 105-mm cannons in the first wave to neutralize beach defenses.25
As of 2022, the PLAGF had six amphibious brigades, each with an estimated 5,000 soldiers and 400 vehicles.26 This does not include the PLANMC’s eight brigades or the PLAGF’s nonamphibious brigades that could be moved in to defend seized islands.27 The sheer volume of these forces makes targeting them all with indirect fires impossible.
In addition, precision munitions are not cheap, and the joint force’s stockpiles are limited. Through war-gaming, the Center for Strategic and International Studies concluded a war with China would outpace the defense industrial base’s ability to resupply the stockpiles. PLA blockades and long-range fires also could deny the joint force and its partners the ability to bring additional weapon systems and munitions into the theater.28 To put it into perspective, a HIMARS battery carries 36 rockets, while an armor company carries 588 rounds. 29 HIMARS should be used against high-priority targets such as enemy ships and airfields, and armor and infantry units should target the more numerous bunkers and enemy tanks.
Recommendations
The joint force lacks the foundational pillars of doctrine, training, education, and equipment to integrate MPF into potential amphibious assaults. Meanwhile, the PLA has positioned itself to become the dominant force in the littoral by investing in its amphibious forces. These issues seem daunting, but the joint force can remedy them if it takes quick action.
First, the Army and Marine Corps must close the doctrinal, training, and education gaps. The Assault Amphibian School should be opened to Army soldiers, and the Army’s MCoE should update its training scenarios and armor doctrine to include amphibious assault. Once the Army has been trained to use MPF in an amphibious assault, the two services should prioritize joint training events that attach Army MPF to Marine amphibious units.
Next, the joint force should acquire the equipment necessary to conduct amphibious assaults. The Army should focus on producing an amphibious tank, perhaps a new model of the M10 Booker. Once the amphibious tank has been finalized, its specifications should be used to create a new LST capable of supporting an integrated amphibious force.
Finally, the joint force must merge the modern and postmodern amphibious assault concepts. The Army’s Multi-Domain Task Force and Marine Corps’ stand-in force cannot seize and hold land independently. They will play a critical role in obtaining sea control, protecting sea lines of communication, and setting conditions for amphibious assaults through preparatory fires and effects, but if used in a vacuum, they will not provide the capability to seize and defend land that will be critical to the joint force in the Indo-Pacific. Prioritizing these concepts at the cost of preparing to conduct MPF-integrated amphibious assaults will lead the joint force to cede island after island to the PLA until it relearns the lessons of history.
1. Todd South, “Goodbye Tanks: How the Marine Corps Will Change, and What It Will Lose by Ditching Its Armor,” Marine Corps Times, 22 March 2021.
2. John Curatola, “Prelude to Liberation: Genesis of American Amphibious Assault in the ETO,” The National WWII Museum New Orleans, 8 November 2022.
3. Kenneth W. Estes, Marines Under Armor: The Marine Corps and the Armored Fighting Vehicle (Annapolis, MD: Naval Institute Press, 2000), 4; and Curatola, “Prelude to Liberation.”
4. Gordon Rottman, U.S. World War II Amphibious Techniques (Elite) (Oxford, UK: Osprey Publishing LTD., 2004), 17–19; and Curatola, “Prelude to Liberation.”
5. Etes, Marines Under Armor, 47–53; and Rottman, Amphibious Techniques (Elite), 20–21.
6. Gene E. Salecker, Rolling Thunder Against the Rising Sun: The Combat History of U.S. Army Tank Battalions In the Pacific in World War II (Mechanicsburg, PA: Stackpole Books, 2008), 116–28.
7. Salecker, Rolling Thunder.
8. Department of Defense, DoD Directive 5100.01: Functions of the Department of Defense and Its Major Components (Washington, DC: U.S. Government Printing Office, 2020).
9. Joint Chiefs of Staff, Joint Publication 3-02: Amphibious Operations (Washington, DC: Joint Chiefs of Staff, 2019), II-9.
10. Army Techniques Publication (ATP) 3-20.15: Tank Platoon (Washington, DC: U.S. Government Printing Office, 2019); ATP 3-90.1: Armor and Mechanized Infantry Company Team (Washington, DC: U.S. Government Printing Office, 2023); and ATP 3-90.5: Combined Arms Battalion (Washington, DC: U.S. Government Printing Office, 2019).
11. MAJ Jessica Rovero, USA, “U.S. Army M1A2 Tanks Train in Australia Alongside Partner Nations for the First Time,” news, U.S. Army Pacific, 1 August 2023.
12. Aaron-Matthew Lariosa, “U.S. and Philippine Forces Defend Island Chain Near Taiwan in Balikatan 2024 Exercise,” USNI News, 9 May 2024.
13. U.S. Marine Corps Assault Amphibian School, Training Command, www.trngcmd.marines.mil/Units/Assault-Amphibian-School/.
14. U.S. Army, “U.S. Army Fort Moore and the Maneuver Center of Excellence,” www.moore.army.mil/.
15. MG Patrick J. Donahoe, USA, and John Spencer, “A Status on the Army’s Preparation for the Next War,” Modern War Institute at West Point, 6 July 2021.
16. Evan Phillips, “LST Redux: Adapting to the Future of Maritime Warfare by Understanding the Past,” Expeditions with MCUP, 21 June 2023.
17. Capt Brian Tuthill, USMC, “Amphibious Combat Vehicles Mark Operations Debut in Pacific During Balikatan 24,” www.imef.marines.mil, 10 May 2024.
18. FY20 Navy Programs, “Amphibious Combat Vehicle (ACV) Family of Vehicles,” www.dote.osd.mil; James King, “Never Bring a Stryker to a Tank Fight,” Modern War Institute at West Point, 2 May 2017; and Salecker, Rolling Thunder, 116–28.
19. Andrew Hills, “120mm Grun Tank M1E1 Abrams,” The Online Tank Museum, 9 May 2020.
20. Howard Altman, “How the Army’s New M10 Booker Light Tank Will Actually Be Used,” The Warzone, 30 January 2024.
21. Joint Chiefs of Staff, Joint Publication 3-18: Joint Forcible Entry Operations (Washington, DC: Joint Chiefs of Staff, 2021), I-1.
22. Katelyn Vazquez, “Join Forces Conduct Jungle Operations Training Course in the Philippines During Exercise Balikatan 24,” Army.mil, 8 May 2024; and U.S. Army Pacific, “#ICYMI: U.S. Army Soldiers Assigned to 2nd Battalion, 27th Infantry Regiment, 3rd Infantry Brigade Combat Team, 25th Infantry Division, Load a CH-47 Chinook Helicopter during Air Assault Operations,” Facebook post, 10 May 2024.
23. Lariosa, “U.S. and Philippine Forces Defend Island Chain.”
24. Meghan Eckstein, “Early Experiments Are Proving Out Tank-Free Marine Corps Concept,” USNI News, 10 February 2021.
25. Connor Kennedy, The New Chinese Marine Corps: A “Strategic Dagger” in a Cross-Strait Invasion, China Maritime Report No. 15 (Newport, RI: U.S. Naval War College, October 2021): 17–19.
26. Dennis J. Blasko, The PLA Army Amphibious Force, China Maritime Report No. 20 (Newport, RI: U.S. Naval War College, April 2022): 3–4.
27. Kennedy, The New Chinese Marine Corps.
28. Seth G. Jones, Empty Bins in a Wartime Environment: The Challenge to the U.S. Defense Industrial Base (Washington, DC: Center for Strategic and International Studies, 23 January 2023).
29. Jen Judson, “U.S. Army Sends HIMARS Rocket Launcher Island-Hopping in the Philippines,” Defense News, 10 May 2024.