The Collapse of 3.0: Rethinking Marine Amphibious Power in the Indo-Pacific
In March 2025, Marine Corps Commandant General Eric Smith testified before Congress that only 13 of the Corps’ 32 amphibious ships were seaworthy. Deferred maintenance, industrial bottlenecks, and congressional indecision have pushed the Marine Corps’ 3.0 Amphibious Readiness Group/Marine Expeditionary Unit (ARG/MEU) model—once the “North Star” of global crisis response—from a deployable force to an aspirational capability. At the same time, the evolving character of warfare—particularly in a high-end conflict with the People’s Republic of China (PRC)—demands a different kind of force. Better suited to operate within the weapons engagement zone, Stand-In Forces (SIF)—small and dispersed Marine units designed to operate persistently in contested areas alongside allies—possess low signatures, high mobility, and the ability to survive and fight. In denied environments like the Indo-Pacific, SIF can maintain contact, disrupt adversary operations, and shape the battlespace for decisive joint action capabilities that ARG/MEUs may be unable to deliver if held at risk or rendered unavailable.
To meet the U.S. Indo-Pacific Command’s operational demands, the Marine Corps must adopt a distributed, scalable force posture centered on SIF. This transition should not entail abandoning amphibious capabilities altogether but modernizing them selectively while prioritizing platforms and operational concepts that reflect the realities of great-power conflict and a contested maritime environment.
The ARG/MEU Model is Currently Unsuitable
The ARG/MEU concept integrates forward-deployed MEUs with three-ship ARGs composed of a Landing Helicopter Dock (LHD) or Landing Helicopter Assault (LHA), a Landing Platform Dock (LPD), and a Landing Ship Dock (LSD)—providing the President and Geographic Combatant Commanders with credible deterrence and decision space across the full spectrum of military operations. Operating as a flexible, sea-based Marine Air-Ground Task Force, the MEUs can conduct amphibious operations, respond to crises, execute limited contingency operations, introduce follow-on forces, and support designated special operations forces. Together, the Navy and Marine Corps employ the integrated ARG/MEU to sustain forward presence, enable rapid power projection, and deliver ground and aviation forces—and their equipment—from the sea to the shore.
The Marine Corps currently maintains seven MEUs—three on each United States coast and one in Japan—while the Navy maintains ten ARGs. This force posture can theoretically support the 3.0 ARG/MEU deployment model, which requires one ARG/MEU each in the Mediterranean, Western Pacific, and broader Indo-Pacific, with relief forces ready to rotate forward every six months. In the 39th Commandant’s Planning Guidance, the 3.0 structure of the ARG/MEU model intends to provide “premier sea basing capability” that delivers “unmatched flexibility without the need to first request access, basing, or overflight” across various theater commands and operations.
In practice, this goal remains aspirational. As of October 2025, the Navy lists 32 amphibious ships in its inventory, yet only 66% are active. Of that number, 19% face proposed decommissioning, making them operationally fragile or politically contested assets. Therefore, only 47% of the amphibious fleet remains fully active. Another 34% remain in maintenance, with many under extended docking restricted availability. Within the Navy’s LSD fleet, 60% are slated for decommissioning, and nine of the remaining LSDs are rated by the GAO to be in “poor material condition.” The LPD fleet, though relatively more modern, also reflects strain: 58% are in or entering maintenance, under construction, or not yet delivered. While the Navy’s two LHA ships—the USS America and USS Tripoli—remain active, the construction of two newer LHAs remains delayed.
An overstretched industrial base and inconsistent congressional direction have deepened the amphibious readiness shortfall. Maintenance backlogs continue to balloon beyond planned durations due to workforce limitations and capacity constraints at public and private shipyards. Simultaneously, the cost and schedule performance of new amphibious construction continues to deteriorate. San Antonio-class LPDs now exceed $1.66 billion per hull, double their initial estimates. Congressional indecision has further muddied force planning: the 2021 goal of 38 amphibious ships has fallen to 32 in 2025, barely meeting the Marine Corps stated requirement of no fewer than 31.
As Admiral James Kilby remarked, “By the letter of the law, we are [ready]; by intent, we’re not.” Despite appearing structurally adequate, the amphibious fleet cannot reliably support the 3.0 ARG/MEU deployment model in practice. The ARG/MEU model, therefore, remains operationally untenable.
The Evolving Threat Environment Demands a New Approach
The return of great power competition, especially with the PRC , has reshaped the strategic environment for United States forces in the Indo-Pacific maritime domain. The PRC has fielded a robust Anti-Access/Area Denial (A2/AD) network, including rocket force with over 2,200 ballistic and cruise missiles, capable of threatening U.S. Navy and Marine Corps movements and survivability during the opening stages of a Western Pacific conflict. These conditions undermine the assumptions behind the Marine Corps’ 3.0 ARG/MEU model, which depends on secure sea lanes, large-deck ships, and rotational presence due to its design around concentrated naval formations that require freedom of movement and predictable logistics to project power forward.
Even if fully resourced, ARG/MEUs are increasingly unsuited to operate within the PRC’s weapons engagement zone. Therefore, the current ARG/MEU is not only aspirational in terms of readiness, but its very design is mismatched with the modern threat environment.
Given the amphibious fleet’s deteriorating conditions and the demands of great power competition, the Marine Corps can no longer rely on the aspirational recovery of a 3.0 ARG/MEU readiness. Instead, SIF must become the centerpiece of forward presence and crisis response, especially in the Indo-Pacific. “SIF are crucial to the Marine Corps’ continued expeditionary relevance,” as Marine Corps Lieutenant Colonels Zach Ota, Dylan Buck, and Brian Strom argue.
SIF are small, mobile, and low-signature units designed to operate within contested environments, particularly in the maritime littorals of the Indo-Pacific, serving as the forward edge of a defense-in-depth strategy. Unlike ARG/MEUs, SIF do not rely on a three-ship amphibious squadron or complex deployment cycles. Instead, they employ Distributed Maritime Operations and Expeditionary Advanced Base Operations concepts to maneuver across key maritime terrain, disrupt hostile plans, gain and maintain contact, and support joint force reconnaissance and counter-reconnaissance efforts. Their “deceptively simple” primary function is detecting and countering threats below the threshold of armed conflict, ensuring the joint force can attack effectively first if hostilities escalate.
Historical precedent supports the value of SIF. The 1943 invasion of Tarawa exposed the limitations of amphibious assaults using ARG/MEU formations. Despite overwhelming naval and air support, U.S. forces suffered over 3,000 casualties in just 76 hours due to insufficient intelligence, fortified enemy positions, and the vulnerability of concentrated formations. In contrast, small, distributed SIF units such as the Marine Raiders and Coast Watchers in the Solomon Islands — used during the Guadalcanal Campaign — achieved outsized effects with fewer resources by disrupting enemy operations, enabling follow-on forces, and securing key terrain.
Adapting Force Design to the Evolving Character of War
Carl von Clausewitz reminds us that while the nature of war endures, its character evolves. SIF proved effective in World War II through agile, low-signature operations, but modern variants must now integrate autonomous, unmanned systems to survive and compete in the maritime environment of the Indo-Pacific.
The Department of the Navy must prioritize investment in autonomous platforms that directly align with the Marine Corps SIF concept. These systems are better suited to the operational realities of the Indo-Pacific operations and offer significant cost efficiencies compared to modernizing and maintaining legacy amphibious platforms.
Programs like the Autonomous Low-Profile Vessel (ALPV)—which cost $6 million, or roughly 0.36% of the costs of building a San Antonio-class LPD— demonstrate how the Marine Corps can conduct distributed operations with minimal training and without the logistical burdens of traditional amphibious ships. During Exercise Valiant Shield 2024, Marines successfully planned and executed ALPV missions after just three weeks of training, remotely operating the vessel from over 6,000 miles away. These programs offer low-cost, rapidly deployable, and operationally flexible capabilities that represent the future of expeditionary warfare. However, they are not without limitations: autonomy brings hard technical limits, operational fragility in high-seas weather and GPS-/Electronic Monitoring-denied environments, and vulnerability to capture or reverse-engineering. Systems like ALPV will require resilient sustainment and supply chains that current logistics pipelines currently struggle to maintain.
Strategically, however, autonomous platforms should be viewed as complementary to SIF rather than substitutive. The optimal posture is a blended force design. To achieve this, the Department of the Navy must avoid committing limited resources to recapitalizing a force structure designed for uncontested environments, like the 3.0 ARG/MEU construct. Instead, the Navy must prioritize recapitalizing platforms central to sea control, such as aircraft carriers, destroyers, and frigates. Meanwhile, the Marine Corps must focus on fielding autonomous systems like the ALPV and investing in resilient command-and-control networks, allied interoperability standards, and industrial capacity for the small, consumable nodes that enhance SIF survivability and effectiveness. This integrated approach allows the Department of the Navy to balance strategic demands with fiscal realities, ensuring that both services remain relevant, lethal, and agile amid renewed great power competition.
Views expressed are the author’s own and do not represent the views of GSSR, Georgetown University, or any other entity. Image Credit: III Marine Expeditionary Force