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The Combined Action
Captain Keith F.
"Of all our innovations in Vietnam none was as successful, as lasting
in effect, or as useful for the future as the Combined Action Program
[CAP]," wrote U.S. Marine Corps (USMC) Lieutenant General (LTG) Lewis Walt
in his memoirs.1 British counterinsurgency expert Sir Robert
Thompson said CAP was "the best idea I have seen in Vietnam."2
The program, undertaken by the USMC during the Vietnam war, was an
innovative and unique approach to pacification. In theory, the program was
simple; a Marine rifle squad would join forces with a South Vietnamese
militia platoon to provide security for local villages. CAP's modus
operandi made it unique. While assigned to combined units, Marines would
actually live in a militia unit's village.
CAP was a response to the conditions in Vietnam. As the senior command
in the I Corps Tactical Zone, the Marines were responsible for securing
more than 10,000 square miles of land that included the five northernmost
provinces of South Vietnam. More than 2-1/2 million people lived in the I
Corps area. Using the militia for local security made sense; there were
not enough Marines to go around.
The Marines and the U.S. Military Assistance Command, Vietnam,
disagreed on war strategies. U.S. Army leaders wanted to search and
destroy the communists in the rural and less-populated areas of South
Vietnam; the Marines wanted to clear and hold the populated areas. CAP was
a manifestation of the strategy the Marines felt best suited the
conditions in Vietnam.
With U.S. Marines living and fighting side-by-side with the Vietnamese
people, CAP seemed to rep-resent an effective, long-term, around-the-clock
commitment to combating the Vietnamese communists at the grassroots level.
CAP worked well in some locations; elsewhere, its results were transitory
at best—with villagers becoming overreliant on the Marines for security.
CAP came naturally for the Marine Corps because counterguerrilla
warfare was already part of the USMC heritage. From 1915 to 1934, the
Corps had a wealth of experience in foreign interventions fighting
guerrillas in Nicaragua, Haiti, and Santo Domingo. For example, the
Marines organized and trained the Gendarmerie d'Haiti and the Nacional
Dominicana in Haiti and Santo Domingo from 1915 to 1934. In Nicaragua
(1926-1933), the Marines organized, trained, and commanded the Guardia
Nacional de Nicaragua. These organizations were nonpartisan, native
constabularies the Marines commanded until host-nation forces could
competently assume command.3
Senior USMC generals in Vietnam had studied as lieutenants such
interventions—called "small wars." But more than that, As Commanding
General (CG), Fleet Marine Forces Pacific, LTG Victor H. Krulak was
responsible for training and readiness of all the Marines in Vietnam. As
CG, III Marine Amphibious Force, Walt directed the operations of all the
Marines in I Corps.
Krulak and Walt began their careers during the 1930s and 1940s under
the tutelage of such Caribbean Campaign veterans as LTG Lewis B. "Chesty"
Puller, Sr., and Major General (MG) Merritt "Red Mike" Edson. In Vietnam,
Krulak and Walt applied the lessons they had learned about guerrilla
When the Marines arrived in South Vietnam in 1965, they occupied and
defended three enclaves in the I Corps area: Phu Bai, Da Nang, and Chu
Lai. CAP grew out of an experiment that Lieutenant Colonel (LTC) William
W. Taylor's 3d Battalion, 4th Marine Regiment, conducted near Phu Bai.5
Taylor's infantry battalion defended 10 square miles and a critical
airfield at Phu Bai. He knew his three rifle companies were not enough to
defend that amount of territory. The local population lived in six
villages, each nominally defended by a militia platoon. Taylor and his
officers brainstormed ideas of how to improve the battalion's defensive
posture. They looked to a previously unused resource—the militia platoons.
Taylor's executive officer, Major Cullen C. Zimmerman drafted a plan to
incorporate the militia platoons into the battalion's defense. He proposed
integrating the militia platoons into the battalion's rifle squads to form
a combined unit.
Taylor liked Zimmerman's plan and forwarded it to Colonel Edwin B.
Wheeler, the regimental commander. Wheeler also liked the plan and pushed
it all the way up the chain of command to Walt and Krulak. Both generals
liked the idea, and Walt sold the idea to South Vietnamese General Nguyen
Van Chuan. Chuan, who was responsible for the Vietnamese military forces
in Phu Bai, agreed to give Walt operational control over the militia
platoons operating in Taylor's sector.
Taylor integrated four rifle squads from his battalion with the six
local militia platoons in early August 1965. First Lieutenant Paul R. Ek
commanded the combined unit, known as a Joint Action Company. Ek, who had
already served as an adviser to a U.S. Army Special Forces unit in Vietnam
and spoke the language, was well versed in coun-terguerrilla warfare. The
Marines in Ek's combined company were volunteers from the 3d Battalion,
4th Marines, and each had been carefully screened by Zimmerman.6
The Phu Bai experiment yielded promising results. The Marines instilled
an aggressive, offensive spirit in their counterparts and gave the militia
something it had never had before—leadership. The Marines also learned
from the Vietnamese, gaining knowledge of local terrain and learning
Vietnamese customs and courtesies. Winning fights against local enemy
guerrillas, Ek's combined unit upset the status quo by driving the
communists out of the villages.
Walt seized on the success of Ek's unique company in Phu Bai and
approached Vietnamese General Nguyen Chanh Thi, his counterpart, with a
proposal to expand the program to include Da Nang and Chu Lai. Walt did
not need to put the hard sell on Thi; he was already impressed by the Phu
Because of Walt and Thi's enthusiasm, CAP stopped being an experiment
and started becoming an integral part of the Marine Corps' war in the I
Corps area. The platoon became the program's basic tactical unit. A 35-man
Vietnamese militia platoon, and a 13-Marine rifle squad, with one attached
U.S. Navy hospital corpsman, formed the combined-action platoon. This unit
lived in and operated out of the local village of the militia platoon.7
U.S. and Vietnamese chains of command remained separate. The Marines
were only supposed to serve as advisers to their counterparts, and they
did—in garrison. In the bush, on patrol, the senior Marine present became
the de facto commander of the combined unit.
From the original 6 platoons at the end of 1965, the number of combined
units grew to 38 platoons by July 1966. By January 1967, 57 combined
platoons operated throughout the I Corps area—31 platoons in the Da Nang
enclave and 13 each in the Phu Bai and Chu Lai enclaves. The number of
combined platoons peaked at 114 in 1970, and the units had spread
throughout the five provinces in the I Corps area.8
Increasing the number of combined platoons caused problems for Walt.
For one, he needed more Marines. He was robbing Peter to pay Paul by
taking men from his two infantry divisions and assigning them to combined
units. Headquarters was not sending Walt more men to make up the
difference. A limit on troop strength in Vietnam had already been set so
as to meet commitments elsewhere.9
To get into CAP, Marines needed to be volunteers, have already served 2
months in country yet still have at least 6 months left on their tours,
have a recommendation from their commanding officers, and once selected,
had to attend a 2-week school, which offered instruction in Vietnamese
language and culture and small-unit tactics.10
Marine infantry commanders were hesitant to release their best
noncommissioned officers for duty with combined units; they knew they
would not receive replacements. And because infantry commanders did not
always give up their best men for CAP, the quality of combined platoons
ranged from outstanding to abysmal, based on the amount of the Marines'
experience, proficiency, and maturity.11
Walt acted on these problems. In February 1967, he appointed LTC
William R. Corson as his Director for Combined Action.12 Corson
was the right man for the job. He had fought with the Marines in the
Pacific and Korea and had completed a tour in Vietnam as a tank battalion
commander. Corson spoke four Chinese dialects, held a doctor's degree in
economics, and had experience in unconventional warfare in Vietnam. He had
also served with the Central Intelligence Agency in Southeast Asia from
1958 to 1959, organizing guerrilla operations against the Viet Minh.13
Corson believed CAP required its own chain of command and objected to
the existing command arrangement that gave local infantry commanders
control of the combined units in their areas of responsibility. He did not
believe the average infantry battalion commander in Vietnam knew what it
took to succeed in the business of pacification. According to writer
Robert A. Klyman, Corson "was there to kill enemy. . . . His mission was
two up, one back, hot chow. Battalion commanders were not in Vietnam to
win the hearts and minds of the people. . . . They were playing the game
of . . . search and destroy. They didn't understand the nature of the war
they were involved in."14
Corson wanted mobility in each of his platoons. "The [combined-action
platoon] will [not] function as the garrison of a so-called `French
Fort,'" he wrote.15 The platoon must "conduct an active,
aggressive defense [of its assigned village] to prevent [communist]
incursions and attacks directed at the hamlet residents and officials."16
In July 1967, Corson drafted a set of standing operating procedures
charging each of his platoons with six different missions:
1. Destroy the communist infrastructure within the platoon's area of
2. Protect public security; help maintain law and order.
3. Organize local intelligence nets.
4. Participate in civic action and conduct propaganda against the
5. Motivate and instill pride, patriotism, and aggressiveness in the
6. Conduct training for all members of the combined-action platoon in
general military subjects, leadership, and language, and increase the
proficiency of the militia platoon so it could function effectively
without the Marines.17
The relationship between the Marines and the Vietnamese militia was the
key to CAP's success. Theoretically, each combined platoon derived its
strength from fusing the two primary elements—the militia soldier and the
U.S. Marine—into a single operational entity. Because the political
climate did not allow Americans to command Vietnamese forces, the Marines
had no formal authority over the militia.18 Walt and Corson
hoped decentralized control and close coordination and cooperation could
resolve any problems caused by this tenuous command relationship.
There were serious problems with the Vietnamese militia. They were
woefully incapable of defending the villages by themselves. One official
account reads: "In general, the equipment and training of the [militia]
platoons and their unimaginative use in static defensive positions made
them a slender reed in the fight against the Viet Cong."19 At
US$19 a month, the militia soldier earned less than half that of his
regular Vietnamese Army counterpart.20 Corruption and graft
were accepted practices, and village chiefs controlled the militia and
padded the muster rolls of their platoons to extort the salaries of
The Marines also had problems. The combined platoons modus
operandi—living and fighting alongside the Vietnamese population—required
the Marines to adapt to a culture radically different from their own. Most
of the Marines were junior enlisted men in their late teens or early
twenties. Expecting men of these ages to quickly adapt to such foreign
surroundings while also serving in a combat zone was a tall order.22
The majority of the Marines who served with combined units from 1965 to
1967 came directly from the infantry. This was not the case, though, as
the war continued. From 1968 to 1970, many Marines joined combined
platoons from rear-echelon support units and lacked basic infantry skills.
In 1969, a senior CAP commander in Quang Tri province wrote of these
shortcomings: "Sound tactics are not God-given; they are not inherited or
acquired automatically. Not one young corporal or sergeant in a hundred
has adequate competence in this field. Their understanding of the proper
use of terrain, the control of the point element, all-around security,
fire and maneuver, fire superiority, fire control and discipline (to say
nothing of the psychological and morale forces involved) leave much to be
desired. In six months, I have yet to see any [combined-unit] leader
working to improve his own knowledge or understanding of tactics.23
Notwithstanding its problems in execution, CAP seemed a viable strategy
for providing local security in South Vietnam. Some analysts speculate
there would have been a much different outcome to the war had the United
States applied the Marines' strategy on a larger scale.24 One
of the main reasons why the program never expanded beyond the borders of
the I Corps area was because General William C. Westmoreland, the senior
U.S. Army commander in Vietnam, subscribed to a different strategy.
Westmoreland believed the regular North Vietnamese Army and main-force
communist battalions posed the greatest threat to the government of South
Vietnam, not the guerrillas operating in the south. He pursued a
strategy through which he could exploit the U.S. advantage in mobility and
firepower to engage the most threatening communist units. After the United
States won the "big unit" war against conventional enemy formations, the
South Vietnamese Army could focus on the "other war" against the
entrenched communist political infrastructure. This formed the
philosophical underpinning for the search and destroy attrition strategy.25
Krulak believed pacification and protection of the South Vietnamese
population—a clear-and-hold approach—was more appropriate than the
search-and-destroy attrition strategy. "If the people were for you," he
wrote, "you would triumph in the end. If they were against you, the war
would bleed you dry, and you would be defeated."26
Westmoreland believed population security was a Vietnamese task.
However, he did write in his memoirs that CAP was one of the more
"ingenious innovations developed in South Vietnam."27
Westmoreland also offered this explanation: "Although I disseminated
information on the [combined action] platoons and their success to other
commands, which were free to adopt the idea as local conditions might
dictate, I simply had not enough numbers to put a squad of Americans in
every village and hamlet; that would have been fragmenting resources and
exposing them to defeat in detail."28
A Viable Approach
By 1970, "a total of 93 [combined platoons] had been moved to new
locations from villages and hamlets deemed able to protect themselves. Of
these former CAP hamlets, the official Marine Corps history of the Vietnam
war claims that "none ever returned to Viet Cong control."29
These figures are spurious at best, as are most other attempts to quantify
the war in Vietnam.
Edward Palm, an English professor and former CAP Marine, is not as
sanguine as the official Marine Corps history: "I would like to believe,
with some, that combined action was the best thing we did [in Vietnam]. .
. . In my experience, combined action was merely one more untenable
article of faith. The truth, I suspect, is that where it seemed to work,
combined action wasn't really needed, and where it was, combined action
could never work.
"The objective was certainly sound. There was a demonstrable need for
an effective grassroots program targeted toward the [communist]
infrastructure, for the most part left intact by large-scale search and
destroy operations. But combined action came too little, too late. The
[communist] infrastructure was too deeply entrenched, literally as well as
figuratively, in some places. They had had more than 20 years to win
hearts and minds before we blundered onto the scene. We were naïve to
think 13 Marines and a Navy corpsman could make much difference in such a
setting. The cultural gulf was just unbridgeable out in the countryside."30
Even at its zenith of 2,220 men, CAP represented only 2.8 percent of
the 79,000 Marines in Vietnam. Yet during its 5-year lifespan, combined
units secured more than 800 hamlets in the I Corps area, protecting more
than 500,000 Vietnamese civilians.31
CAP was not the magic ingredient that would have won the war in
Vietnam, but it was a viable approach to counterguerrilla warfare, worthy
of further study. What better way was there for learning about the enemy
in such a war than fighting with the militia and living with the local
populace? No wonder CAP Marines became some of the best sources of
intelligence in the Vietnam war as well as some of the best small-unit
leaders. They had to be, operating as they did, in order to survive. Air
strikes, free-fire zones, and massive demonstrations of firepower were
commonplace throughout South Vietnam, but such were rare occurrences near
villages with combined-action platoons.
The Battle for Hue City and the siege at Khe Sanh dominate the
literature about the Marines in Vietnam. CAP, however, was the Corps'
greatest innovation during the war. MR
1.Lewis W. Walt, Strange War, Strange Strategy: A General's Report
on the War in Vietnam (New York: Funk and Wagnalls, 1970), 105.
2.Quoted in Andrew F. Krepinevich, Jr., The Army and Vietnam
(Baltimore, MD: Johns Hopkins, 1986), 174.
3.On the Marines in Nicaragua, see Neill Macaulay, The
Sandino Affair (Chicago: Quadrangle Books, 1967). On the Marines in
Hispaniola, see Hans Schmidt, Maverick Marine: General Smedley
D. Butler and the Contradictions of American Military History
(Lexington: University Press of Kentucky, 1987), 74-95. See also
Graham A. Cosmas, "Cacos and Caudillos: Marines and Counterinsurgency in
Hispaniola, 1915-1924," in New Interpretations in Naval History:
Selected Papers from the Ninth Naval History Symposium, William R.
Roberts and Jack Sweetman, eds. (Annapolis, MD: Naval Institute Press,
1991), 293-308. For a comparison of CAP with the constabularies the
Marines organized in Latin America, see Lawrence A. Yates, "A
Feather in their CAP? The Marines' Combined Action Program in Vietnam," in
4.Victor H. Krulak, First to Fight: An Inside View of the U.S.
Marine Corps (Annapolis, MD: Naval Institute Press, 1984), 190-1;
Walt, 29; Jon T. Hoffman, Once a Legend: "Red Mike" Edson of the Marine
Raiders (Novato, CA: Presidio Press, 1994), 98, 122-3. Puller and
Edson, who served with distinction as officers in the Guardia Nacional de
Nicaragua, also served successively as small-wars instructors during the
1930s. Walt and Krulak were their students and, as captains, served with
Edson and Puller in the Pacific during World War II.
6.Robert A. Klyman, "The Combined Action Program: An Alternative Not
Taken" (Honors thesis, University of Michigan, Ann Arbor, 1986), 4-5;
Michael Duane Weltsch, "The Future Role of the Combined Action Program"
(Master of Military Art and Science thesis, U.S. Army Command and General
Staff College, Fort Leavenworth, 1991), 57-65.
7.III MAF [Marine Amphibious Force] Force Order 3121.4A, sub [subject]:
SOP [Standing Operation Procedures] for the Combined Action Program, dtd
[dated] 17 July 1967 (hereafter, CAP SOP), in CAF [Combined Action Force]
History and SOP Folder, Box 2, Pacification Study Docs [Documents], Marine
Corps Historical Center (MCHC), Washington, DC; Jack Shulimson, U.S.
Marines in Vietnam 1966: An Expanding War (Washington, DC: History and
Museums Division, HQMC, 1982), 239-43; Gary L. Tefler, Lane Rogers, and V.
Keith Fleming, Jr., U.S. Marines in Vietnam, 1967: Fighting the North
Vietnamese (Washington, DC: History and Museums Division, HQMC, 1984),
186-95; William R. Corson, The Betrayal (New York: W.W. Norton,
8.Shulimson, 239; Tefler, et al., 187; Weltsch, 65.
10.CAP SOP; Corson, 183-4; Edward F. Palm, "Tiger Papa Three: A Memoir
of the Combined Action Program," Marine Corps Gazette (January
1988), 35; CAP School syllabus, 21 August-1 September 1967, and CAP School
diploma, dated 25 February 1969, in Michael E. Peterson, "The
Combined Action Platoons: The U.S. Marines' Other War in Vietnam" (M.A.
thesis, The University of Oregon, Eugene, 1988), 285-91. Peterson is a CAP
veteran. Praeger Publishers published this thesis in 1989.
11.Ltr [Letter], CG [Commanding General], III MAF to CG FMFPac [Fleet
Marine Force Pacific], sub: Combined Action Group Headquarters,
Organization, Equipment, Functions and Concept of Operations, dtd 4 May
1967, MCHC; Ltr, CO [Commanding Officer], CAF to CG, XXIV Corps, sub:
CORDS [Civil Operations for Rural Development Support] Survey of CAP
Villages, dtd 24 March 1970, MCHC (hereafter, Ltr, CO, CAF). See also
Ronald H. Spector, After Tet: The Bloodiest Year in Vietnam (New
York: The Free Press, 1993), 195; Shulimson, 240; Klyman, 13. Klyman
quotes Colonel G.E. Jerue, a former regimental commander in the 3d Marine
Division: "Although the requirement states that they [CAP Marines] should
be volunteers, it doesn't demand volunteers. We more or less had to go by
the rule of thumb that if the man doesn't object, he is a volunteer for
13.Peterson (Praeger), 39-41.
17.Ltr, CO, 4th CAG [Combined Action Group] to 4th CAG CACO [Combined
Action Company] Commanders, sub: Tactical Operations, Policies and
Guidance, dtd 14 January 1969, MCHC (hereafter, Ltr, CO, 4th CAG); Corson,
174-98; CAP SOP.
18.CAP SOP; Corson, 183-4; Palm, 35; CAP School syllabus and CAP School
diploma in Peterson, 285-91.
19.Richard A. Hunt, Pacification: The American Struggle for
Vietnam's Hearts and Minds (Boulder, CO: Westview Press, 1995), 34-35.
20.Russel H. Stolfi, U.S. Marine Corps Civic Action Efforts in
Vietnam, March 1965-March 1966 (Washington, DC: Historical Branch, G3
Division, HQMC, 1968), 39.
21. Krulak, 187-189; David H. Wagner, "A Handful of Marines," Marine
Corps Gazette (March 1968), 45; Hunt, 91.
23.See Ltr, CO, CAF.
24.Ltr, CO 4th CAG.
25.Krepinevich, 172-7. Krepinevich argues in favor of expanding
combined action throughout Vietnam. Unfortunately, his approach does not
take full account of the recruiting problem that would accompany such an
expansion. Spector highlights a few of the problems: "The ideal CAP Marine
was a cool and efficient infantry fighter, not only expert in the skills
of combat but able to impart these skills to an untrained, uneducated
farmer who spoke little or no English. At the same time, he was a patient,
subtle, and resourceful community organizer, able to overcome cultural
barriers and prejudice to win the hearts and minds of the villagers. Such
men, if they existed at all, were in short supply" (195).
26.George C. Herring, America's Longest War: The United States and
Vietnam, 1950-1975, 2d ed. (New York: McGraw-Hill, 1986), 150; Allan
R. Millett and Peter Maslowski, For the Common Defense: A Military
History of the United States of America, rev ed. (New York: The Free
Press, 1993), 580; Phillip B. Davidson, Vietnam at War: The History,
1946-1975 (New York, Oxford University Press, 1991), 352-4; William C.
Westmoreland, A Soldier Reports (New York: Dell, 1980), 215-6.
27.Krulak, 194; see also Neil Sheehan, A Bright and Shining
Lie: John Paul Vann and America in Vietnam (New York: Random House,
30.Graham A. Cosmas and Terrence P. Murray, U.S. Marines in Vietnam:
Vietnamization and Redeployment, 1970-1971 (Washington, DC: History
and Museums Division, HQMC, 1986), 149. For a description of a successful
combined platoon, see Francis J. West, The Village (Madison:
University of Wisconsin Press, 1985). West tells the story of the Binh
Nghia combined platoon, which operated from May 1966 to October 1967 near
32.III MAF Combined Action Force Deactivation Ceremony Program, dated
21 September 1970, in Peterson, 334-5.