CORPS Competency?

III Marine Amphibious Force Headquarters In Vietnam

Reviewed by Arrigo Velicogna

Article published on: September 1, 2025 in the Army History Fall 2025 Issue

Read Time: < 5 mins

University Press of Kansas, 2024

Pp. xvi, 331. $54.99

In Corps Competency?: III Marine Amphibious Force Headquarters in Vietnam, retired Marine Corps lieutenant colonel Michael F. Morris sets out to judge the performance of the U.S. Marine Corps' III Marine Amphibious Force (MAF) in Vietnam as a corps-level command. It is a welcome approach to a topic usually dominated by tactical studies or campaign histories. The book presents a high-level approach to marine operations in Vietnam, focusing, as the title implies, on the corps level.

Morris quickly outlines his thesis: that the III MAF failed as a field corps organization. The more the book goes into details, the longer the litany of failures grows. Staff billets in Da Nang resembled musical chairs more than proper assignments. In several cases, critical positions such as operations and intelligence saw appointments made in weeks rather than months. Operational matters were left to division commanders with little to no input from the MAF headquarters. Units were broken up and reassembled without pause, with battalion headquarters going into actions commanding everyone else’s companies rather than their own. Although Morris credits the III MAF with being able to ad-lib a system to satisfy logistical needs successfully, improvisation and extemporization, rather than planning, were the norm. The system was also a success because of the U.S. Navy. The MAF concept cracked under the pressure of an outsized span of command. A headquarters is designed to control one Marine division, and one Air Wing controls up to five divisions, and an Air Wing twice its supposed size. One wonders, as the author does, why the Marines never actually activated and deployed a Marine Amphibious Corps Command rather than a MAF.

The book is also scathing in its analysis of the MAF’s effectiveness in achieving results. According to Morris, the III MAF had three primary goals: to keep the Viet Cong down, to prevent the North Vietnamese from advancing, and to build up the South Vietnamese army (ARVN). Achieving any two of these three goals would have ensured success. Yet the III MAF failed at all three. Although the MAF placed a great deal of emphasis on pacification (the hybrid war), it focused entirely on the Combined Action Program, excluding everything else. Training the ARVN was neglected and dumped on the U.S. Army. Again, the Marines appeared to be focused single-mindedly on training their local counterpart, the Vietnamese Marine Division. The author is extremely critical of the III MAF’s unwillingness to work closely with the ARVN I Corps in joint operations. The few combined operations attempted early in Lt. Gen. Lewis W. Walt’s command were failures, often because of marine bungling rather than Vietnamese incompetence. Although it could be argued that III MAF lacked the resources for another daunting task, it was no excuse. In “keeping the North Vietnamese out,” III MAF certainly was hamstrung by restrictions from above, a fact that the author emphasizes. In the end, it was the MAF emphasis on strategic defense and operational offense, and its inability to reassess its tactics, properly evaluate its opponents, and exercise effective command and control, that caused failure. Here, Morris is particularly critical of Lt. Gen. Robert E. Cushman Jr.’s tenure, especially during the first critical days of the 1968 Tet Offensive.

One of the most intriguing arguments in the book is Morris’s approach to the controversial McNamara Line—an effort to create a defensive barrier to detect and prevent North Vietnamese cross-border infiltration. Historians usually have criticized the project, accepting General Cushman’s conclusion that it was a “stupid idea.” Morris instead argues that the plan had merits and that III MAF missed an opportunity in not completing it. The argument in support of the project is twofold. First, the anti-infiltration barrier would have provided III MAF with enhanced early warning of enemy incursions, helping the mobile defense strategy used by the Marines. Second, if the barrier proved effective in reducing infiltration across the Demilitarized Zone, III MAF could have made a clear case to extend a manned barrier into Laos. Although it was not certain the White House would have approved, it at least would have represented a serious alternative to the failing strategy. Morris cogently notes that the Marines were not opposed to barriers at all, having built a similar structure to protect their installation at Da Nang.

For those accustomed to publications that lavish praise on Marine Corps operations in Vietnam, often authored by serving or former Marine officers, 40 ArmyHistory FALL 2025 Corps Competency? represents a valuable and serious counterpoint. Furthermore, the author’s criticism is supported by substantial evidence, making it difficult to refute. As with every human endeavor, Corps Competency? is not perfect. Although the author demonstrates the III MAF commitment to civic action with impressive statistics, he ignores the even more impressive numbers coming from U.S. Army formations. He also skips over the poor state of combined arms tactics in 1965, a product of the Marine Corps leadership’s fascination with helicopters. Yet these are minor flaws that do not detract from the book’s main analysis.

Corps Competency? does not present III MAF in a glowing light. In Vietnam, the Marines showed the ability to learn and adapt at the tactical level. However, their major command in Vietnam failed to properly analyze the situation on the ground, adapt to it, and exert effective control over its forces. The reasons for this abysmal failure are tied to service (or strategic) culture and personalities. Marine Corps training and education were focused on battalions and regiments. Marine doctrine was centered on amphibious assault and Marine Air-Ground Task Force concepts to the exclusion of anything else. On top of these issues, only a few of III MAF’s commanders showed an aptitude for higher command. Most delegated authorities and responsibilities to an ad hoc staff that often could not cope. Even worse, the Marine Corps itself failed to learn any relevant lessons on corps command from the war, opting instead to select only lessons that supported its doctrine.

With the Marine Corps again undergoing a significant structural change, and with a new, unproven, and, according to some, unsuitable littoral combat concept at its center, one could wonder if history is repeating itself.