CAP History

(The following is a brief general history of the Combined Action Program.  See CAC Oscar History for details about our unit history.)

The Combined Action Program was for many years merely a footnote in history.  Only a handful of publications dealt with this unique program that had held such promise. 

In recent years, that has changed somewhat with the introduction of books and studies on the program, and a renewed interest in the concept for the wars in the Middle East, and attempts to introduce a similar concept in Iraq.

There are a few seminal works on Combined Action (especially; “Combined Action Platoons: The Marine's Other War In Vietnam” by Michael E. Peterson (Praeger Publishers, NY, stemming from Michael’s MA thesis)  and the reader is directed to them for detailed studies of the program and its components.  (See the bibliography for details, and the notes, which include various works on the CAP by people who were associated with it or have studied it comprehensively.)  

The following background information is drawn from a number of sources, including those above, and those cited in the text and notes.  

My sincere thanks to those who have contributed their work, and allowed me to reprint it here.  These include LCOL James H. Champion, USMC (Ret.) whose articulate and insightful essay on CAP is included in CAP Articles.

I have also drawn upon the excellent work of MAJ Keith Kopets, USMC, whose article on the program has appeared in the Marine Gazette, Combined Arms Center Military Review (July-August 2002), and elsewhere. (I am still trying to get in touch with  MAJ Kopets, if anyone is in contact with him, but the Marine Gazette has kindly granted me interim permission to publish the version they printed.)

I have tried to attribute all quotes and articles correctly, and get formal permission for all reprints, but there are some I know I have failed to attribute or locate.  Part of this is due to the fact that I have been collecting this information for years, and unfortunately some of the notes have been lost or separated from their authors.  If any readers can assist me by identifying or putting me in touch with the authors and photographers who are unattributed, please do so.


The CAP program was developed by the U.S. Marines in 1965, originally from a single platoon.  The program grew as the concept became a matter of interest to the Marine command structure.  

Theoretically, a Marine rifle squad and a Navy Hospital Corpsman (medic) were melded with a Vietnamese Popular Force (militia) platoon to provide security for villages from the Viet Cong forces. (In practice, CAPs were seldom up to full T.O. strength.)  

The Marines originally lived in the villages (later CAPs became "mobile"). In theory, they trained the RFs, conducted joint patrols and ambushes, and engaged in "Civic Action" work, which included medical care for the villagers, helping them with things like wells, schools, and other projects that benefitted the people.

At first the Marines were drawn from local line companies, but eventually the program became somewhat more formal, with Marine volunteers "trained" in the Combined Action School at Da Nang. Although a good idea in theory, the schools were too short and shallow to be of much real use, and your real training was (as with so much else in the Marines) "OJT."  The graduates were then assigned to Combined Action Companies in the field, where they were assigned to squads, usually one to a village, though headquarters CAPs were sometimes "double" CAPs of two squads.

By 1969, (despite heavy losses during Tet 1968), there were 19 companies with 102 platoons, and four Combined Action Groups, spread over I Corps.  CAPs peaked in 1970, with 4 Groups, and 114 companies, spread through the 5 provinces of I Corps.


The CAP concept seems to have been at least partially based on Marine pacification programs in Haiti, Nicaragua, the Dominican Republic, and elsewhere, during the "Banana Wars" in the late 19th and early 20th centuries. 


In these programs, the concept was that Marine units would pacify and administer regions, while providing training, security, and civic action projects for local forces and villages.  (Again, I will avoid discussing the underlying political aspects of these actions, as there are differing interpretations, and it is beyond the scope of this work.)  

Opinions differ about exactly how and where Combined Action originated, but it seems to have started in August 1965 as a unit drawn from 3d Battalion, 4th Marines, under LCOL William W. Taylor in the Phu Bai area.

3/4’s TAOR included 6 villages and an airfield in a ten square mile area. The unit was overextended, and Taylor's XO, MAJ Cullen C. Zimmerman, suggested that they incorporate local RF/PF militia units into 3/4's operations. 

Taylor sent the plan to COL E. B. Wheeler, 4th Marine Regt. CO, who forwarded it to III MAF and FMFPAC. MAJGEN Lew Walt and LTGEN Victor Krulak, both of whom had trained under Banana War veterans, saw the potential value and agreed to the proposal. GEN Nguyen Van Chuan, the local ARVN CO, gave Walt  control of the PF platoons near Phu Bai.

Taylor integrated four squads with the  local PF units in  August 1965.  1LT Paul R. Ek was designated as unit commander. (Ek had some training in Vietnamese and counterinsurgency operations.) 

The US troops were (at least theoretically) handpicked volunteers from 3/4, carefully screened by the executive officer, Maj Zimmerman. 

The late LCOL William R. Corson and the COL Edward Danowitz were also important figures in the program


MGEN Walt formalized the program in February 1967, appointing LCOL William R. Corson as the III MAF deputy director for combined action. (See In Memoriam for the obituaries of these influential officers.)

LCOL Corson was  a combat veteran of World War II and Korea. He spoke four dialects of Chinese, held a doctorate in economics, and had experience in unconventional warfare, having worked with the CIA from 1958-59 organizing the Meo hill tribes for guerrilla operations against the Viet Minh in Vietnam. 

Corson believed CAP should have a separate chain of command, as it was his opinion that the average battalion commander in Vietnam often didn’t know or care how to succeed in combined action, since they were trained and oriented toward offensive large-unit warfare. Corson saw CAP as being mobile and offensive in nature, a concept which later took shape in the mobile CAP units.

However, Corson was very disturbed by what he saw happening in Vietnam.  When he returned to the US, he was made deputy director of the Southeast Asia Intelligence Force in the office of the assistant secretary of defense.  He was by then convinced that U.S. policies in Vietnam were doomed and he wrote a book called; "The Betrayal" (1968, W.W. Norton and Co. Inc.) In it he stated that the Saigon government was corrupt and incompetent (often true enough in my experience) and that it commanded no real loyalty from most of the Vietnamese. Unless the United States revised its policies and the RVN government reformed, the war would be lost, and the lives of our servicemen wasted.

Publication was set for July 1, 1968, a month after LCOL Corson was scheduled to retire from the service. Marine Corps regulations require officers on active duty to submit statements on policy for review before making them public. Corson claimed that this did not apply to him because the book would not go on sale until after his retirement. 

The Marine Corps responded by postponing his retirement and planning to convene a general court-martial. This was dropped on the grounds that they would only serve to draw attention to the book. Colonel Corson's retirement went through a month later than originally scheduled, and the book was published anyway. It is well worth reading, though hard to find.

Essentially, Corson, like Billy MItchell, was attacked for daring to speak the truth, as he saw it, to power.  This has happened more than once in American military politics, and indeed, happened to GEN Eric Shinseki at the outset of the invasion of Iraq when he correctly predicted to SecDef Rumsfeld and VP Cheney that it would require 430,000 "boots on the ground" to hold a post-invasion Iraq. His advice was ignored to our great cost, until GEN Petraeus adopted a modified form of it for his "surge" which temporarily alleviated the problem.

CAP School

Despite its rocky start, CAP became an official "hearts and minds" civic action program, and as mentioned above, a school of sorts was eventually established near Da Nang in an old French compound. Training was brief (ten days) and covered a few bare essentials - some Vietnamese phrases, customs, and culture, some civic action precepts, and some military topics.  Far too short to be of much good, frankly, though a step in the right direction.  Upon graduation, you were posted to your unit. Eventually they began issuing certificates showing you had graduated.

CAP School Certificate, 1970
(Photo above by Sandy Wardlaw of his certificate, used with his kind permission.)

CAP School Compound at Da Nang, c. 1968
(Color photo above by Tom Harvey, CAP 3-3-5, used with his kind permission.)

View of the CAP School Compound at Da Nang, c. 1967-8

(Does anybody know who took the B & W picture above so I can credit them?)

Initially, CAP Marines were issued a special cloth and leather insignia to be worn from the button on the breast pocket of the uniform jacket.  

Original CAP Insignia

(Later superseded by the enameled metal badge at the top of the page)

Part of the reason for the change was that the original acronym CAC (for Combined Action Companies) had by now been identified as a source of great mirth among the Vietnamese. (See below for that story!)  Note the new badge that replaced this (top of page) says Combined Action Program. 

CAP Grows

The CAP concept in Vietnam was opposed by some who considered "hearts and minds" programs a waste of money, men, and materiel.  CAPs were often ignored at best and despised at worst by many area commanders. The prevailing concept was; "Get 'em by the balls and their hearts and minds will follow."  While there may be some merit to this idea, it is not a great way to win lasting friends, and those with this attitude practicing this form of "pacification" only made the CAP Marines' job that much more difficult.

However, the concept eventually gained backing from Marine generals Wallace Greene, Victor Krulak and Lew Walt, and with their support, the program expanded.  

By 1969, despite losses during the 1968 Tet Offensive, the program had expanded to 102 platoons comprising 19 companies and 4 groups, and was even mentioned by President Lyndon B. Johnson in a speech. (See notes.)  CAPs peaked in 1970, with 4 Groups, and 114 companies, spread through the 5 provinces of I Corps. 

Eventually, even the Army had a form of CAP - US Army Civil Action Patrol Team (similar to the Marine CAP on a smaller scale).  Typically they were a 3-man team including an officer, enlisted instructor and RTO.  The HQ was in a nominally secure area, and they ventured out to arranged meeting places to provide instructional support in weapons maintenance, etc.  One such element  was an adjunct of the 1st/502d Inf, 101st  ABN and was sited at Eagle Beach in June 1970. (The foregoing was received from an Army “CAPT” member, "M-60" Mike Kelley.)

Marine Combined Action units, by comparison, lived in the villages, taught military subjects to the indigenous population, helped fortify and defend the villes against the VC and NVA, ran joint patrols with the local "Regional Force" and / or "Popular Force" militia, known from their initials (RF / PF) as "rough-puffs."  They also assisted in civic action projects (such as roads, wells, schools, etc.). 

According to CAP vet David Sherman, "Some of the first units were called "JACs," "Joint Action Companies." The "Joint" was changed to "Combined" because in military parlance, "joint" means combined forces of one nation, "combined" means forces of more than one nation, and so they became "CACs," "Combined Action Companies."  

That was later changed to "CAP," "Combined Action Platoons (or Program)"  The last phase, when Marines were no longer permanently assigned to individual villages, was called "CUPP," the "Combined Unit Pacification Program."

The units were still known as CAC (Combined Action Companies) when I first joined them, but the name was later changed, partly for linguistic reasons - "cặc" is a slang word for the male generative organ in Vietnamese.  This was compounded by the fact that the motto at the top was the phrase " sức mạnh " which means roughly strength or something sturdily built. The obvious implications were very humorous to the Vietnamese, who would walk by and giggle as they saw our camp sign.  

The new badges bore the phrase "Combined Action Program" at the top, with the new motto "LÚC LƯƠNG HƠN HỢP" meaning roughly (I believe) "With Reward(s) Over Time"

There remained some overlap and confusion regarding the various names all through my time in the units (1967-8).


Individual units were assigned to villages in an (ostensibly) “pacified” area, usually one to a village, though they might serve several other villages in the area.  

Headquarters CAPs were sometimes “double” CAPs - i.e.; two CAP squads, one comprising the HQ personnel, the other the patrol and defense element. 

Initially, they were identified by letters and numbers, like line units, though later by numeric designators. They were organized as Combined Action Platoons (CAPs), which in turn formed Combined Action Companies (CACs) which were in turn organized into Combined Action Groups (CAG).  As mentioned, eventually there were four CAGs in I Corps.

During the late 1966-67 period, some of the CACs were under Sub Unit #4, an administrative division of HQ 3rd Marine Division (Reinforced). Oscar was one of these. Later, they operated under Sub Unit #5, then returned briefly to SU #4, and finally came under the control of III MAF.

According to the Command Chronology of HQ 3rd Marine Division (Reinforced) dated 10 November 1966 (provided by Larry Larsen, formerly of Sub Unit #5), “Combined Action Company joined our rolls as Sub Unit #4 on 14 October 1966.”  

The  Command Chronology’s “Narrative Summary” for December 1966 mentions various branches supporting CACs Alpha at Hương Thủy (a county-level town of Thừa Thiên–Huế Province in the North Central Coast region of Vietnam, which I later served in), and Hotel (Phu Loc), and a fourth portion of HQ 3rd MarDiv (Rein) deployed to Khe Sanh in support of the Senior Officer Present.  

It had been determined that a Combined Action company would be established and headquartered in Khe Sanh Village (XD 846380) at the site of the 
Huong Hoa Sub-Sector HQ, 
and plans were completed with the Huong Hoa Sub-Sector Chief for the establishment of 
three Combined Action Platoons (CAPs).  (SOP 031530 / Feb 67, SITREP #3)

In February 1967, the Narrative Summary of the HQ 3rd MarDiv (Rein) notes the establishment of Sub Unit # 5 at Khe Sanh.  This corresponds to the establishment of Oscar Company, and the arrival of three platoons on the morning of 5 February at 0945.  (SOP 051315Z / Feb 67)  The company was officially established in Huong Hoa 
 Headquarters in Khe Sanh Ville. (SOP 061414Z / Feb 67, SITREP #6) 

These official accounts more or less coincide with oral accounts given by the late Steve Green  (see In Memoriam), a "plank-crew" member of O-2 (who gave a date of about 2 Feb 1967), and that of  Larry Larsen of SU #5, who states that CAC Oscar was part of Sub Unit 5 from 1 February until 15 July 1967.  (At that time they were reassigned to Sub Unit #4 which was headquartered in Phu Bai.)   

The company consisted of the HQ and 3 CAPs.  HQ / Oscar 1 were in "downtown" Khe Sanh village in the Huong Hoa 
 Headquarters compound, augmented by 2 platoons of the 915th Regional Force Co. (ARVN).  There were also a small team of US Army advisors under MAJ James Whitenack (later replaced by CPT Bruce B. G. Clarke) for a total of approx. 178 men.

Outlying units were Oscar 2 (XO 843380), on the north side of Hwy. 9 at the western end of the village, about 200 meters west of O-1and Oscar  (XD 841408)  assigned to Ta Cong Village in Khe Sanh Valley, originally located on the South side of QL-9 approximately 800 meters south of the west end of the main Khe Sahn Airfield. (See CAC Oscar History for details.)

On 15 July 67, the CC notes that SU #4 was assigned TAD to III MAF, and on 29 July 67 that the CAC personnel of SU #5 were reassigned to SU #4.  

In October 1967, the CC notes that “the 3rd Combined Action Group (CAG) was activated as a separate unit under III MAF (operating out of Phu Bai) effective 1 October 1967.  The remaining 1 officer and 16 enlisted in SU #4 continued to function as CAG members until normal attrition reduced them to zero effective 30 November 67.  

CAP units c. 1970.  Note that Quang Tri is now 4th CAG

(Oscar was in 3rd CAG - 4th wasn't established then.)

(Source: submitted by Fred Dorr)

The End of CAP

In 1970, III MAF reduced the CAP platoons as it redeployed its regular forces. On 21 September 1970, the Marines officially deactivated CAP as a separate command within III MAF. 

In its 5 years of operation, CAPs operated in more than 800 hamlets, containing approximately 500,000 Vietnamese civilians in I Corps. 


On a personal level, many CAP Marines remember fondly their former allies. (This is particularly true of those of us who worked with the Bru tribe of the Dega ("Montagnard") people.)  Some of the friendships established then have lasted to the present.  Indeed, some CAP Marines have gone back to Vietnam at their own expense, and found the people still remember them kindly. Some of the former CAP personnel (as well as some of the Special Forces personnel) have traveled back to establish or work in charitable and civic action programs doing work similar to that which won them friendship originally.

Unfortunately, their very success also made them prime targets of the VC and later the NVA, who often specifically targeted them.  (It has been said that CAP NCOs and officers, and even entire units had a price on their heads in some areas.)  

Their small size and remoteness made them vulnerable to enemy assaults, and though the enemy usually paid a high price for it, units were often over-run, at times with few or no survivors. Several CAP Marines are one of a handful of their units who survived.  One is the sole survivor of his unit.  

Some writers, including Army and Marine flag officers, speculated there might have been a much different outcome to the war had the United States applied the principles of combined action sooner throughout all of South Vietnam.

GEN William Westmoreland was not an advocate of pacification programs.  He believed in large unit land warfare, and was trying to arrange for a full-scale land battle with the NVA that would ostensibly break them for once and all. Nonetheless, he wrote in his memoirs that the Combined Action Program was "one of the more ingenious innovations developed in South Vietnam.

In 1966, Harold P. Ford, who held senior positions in both the National Intelligence Council and the Directorate of Operations, offers some insights on Secretary of Defense Robert McNamara's evaluation of the situation in Vietnam; "The large-unit operations war, which we know best how to fight and where we have had our successes, is largely irrelevant to pacification as long as we do not have it. Success in pacification depends on the interrelated functions of providing physical security, destroying the VC apparatus, motivating the people to cooperate and establishing responsive local government.

According to LCOL James H. Champion, USMC (Ret.) a former CAP officer; "In April and May 1969, 1st CAG killed 440 VC or NVA, and 1st CAG was killing more NVA than the entire 101st Airborne Division. 1st CAG had about 400 Marines and sailors at the time."  Elsewhere in his article he states: “From 1966 until 30 June 1969 they {CAP NCOs} lead small units which killed over 4400 VC/ NVA.” (See the entire article in CAP Documents and Articles.) 

Khe Sanh veteran Peter Brush wrote, "Civic action had promise. Had it been adopted on a wide scale the war would have been different, but it is a matter of speculation as to whether it would have ultimately affected the outcome."    (Excerpt from  "Civic Action: The Marine Corps Experience in Vietnam" published in Viet Nam Generation, Vol. 5:1-4, March 1994, pp. 127-132.)

Other writers, including MAJ Edward Palm (himself once a CAP Marine) thought otherwise.  "I would like to believe, with some, that combined action was the best thing we did... ...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." 

Since it was never tried on a large scale or with adequate resources, we will never know for sure.

It is of some interest to note that the forces in Iraq reintroduced a version of the CAG concept, and I watched that process unfold with great attention.  However, it seems that once again it was a belated strategy only taken when "Shock and Awe" concept had won the war, but failed to secure the peace.  Sadly, as in the case of CAP in Vietnam, it seems to have amounted to “Too little, too late.”

(Note: This site represents the result of many years of investigative work and research. I have tried to be as accurate throughout as possible, but there is no such thing as 100% perfect. In cases where I was not present, I have relied on the accounts of those who were present and / or  official records, correspondence, statements from comrades, friends and family, and other sources. Statements, quotes, poems, or any material other than my own reflect the views of those who made them. Neither this author nor this site assumes any responsibility for any errata made in good faith, nor for any of the views expressed other than my own. All the photos, documents, text, and other materials are copyright, and they belong solely to the authors, photographers, etc., who retain all rights to the materials.  All material is copyright, and may not be used without express written permission of the owners or their heirs and assigns. All material used with the express permission of the owners, who are named where known. Unattributed material will be attributed when the owner contacts me.)

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