The Republic of Vietnam was divided into four corps-sized tactical zones during the Vietnam War. Generally, a corps consists of three infantry divisions and additional supporting units. This is not to say that three infantry divisions were always present inside each tactical zones (also known as CTZs), but rather, how war planners in Saigon decided to manage the war in South Vietnam. The northernmost of these CTZs was the I Corps Tactical Zone (also, I CTZ).
In terms of square miles, I CTZ was a massive area — the size of which necessitated dividing the zone into smaller regions labeled Tactical Areas of Responsibility (TAOR). The senior American military commander in I CTZ was the Commanding General, III Marine Expeditionary Force. His command included two Marine Divisions, two Marine Air Wings, a U.S. Army infantry division, several Army aviation companies, and a substantial logistical footprint. Within each of the “major command” TAORs were smaller TAORs, usually assigned to brigades or regiments and broken down further into battalion TAORs.
Form follows function
This arrangement was complex but necessary because the war itself was problematic. Not only were there U.S. Army and Marine Corps units fighting in Vietnam, but there were also U.S. Navy and Air Force units — and all of these were operating along with South Vietnamese military units (Army, Marine Corps, Navy, and Air Force). What made this even more confusing was that Marine Corps regiments (three battalions each) frequently “loaned” their battalions to other regiments, either as reinforcing organizations or as a replacement for battalions that had suffered significant numbers of casualties (making them ineffective in combat). So, for example, battalions of the 5th Marines, 7th Marines, and 27th Marines might operate under the control of the Commanding Officer, 7th Marines, or just as easily be assigned to serve under another regiment’s TAOR. In this story, elements of all three regiments operated together in a single combat operation known as ALLEN BROOK in the spring of 1968.
At the beginning of 1968, both the Marines at Da Nang and the communists operating in Quang Nam Province were preparing to launch offensive operations against one another. Initially, the enemy confined its activities to guerrilla-styled warfare; information from Marine Corps reconnaissance forces (known as Stingray) seemed to indicate that the communists were re-infiltrating previously held positions in I CTZ. Of particular concern to the Marines was the repopulation of communist forces in the area of Go Noi Island. The island was formed by the confluence of the Ky Lam, Thu Bon, Ba Ren, and Chiem Son Rivers, some 25 13 miles south of Da Nang.
Here’s what happened
One might note that U.S. Marines are good at many things, including finding suitable names for God-forsaken places. Vietnam offered an almost unlimited opportunity for Marines to identify and then name some of the worst places on the earth. They named one of these places Dodge City. They called it that because it was an area where gunfights were almost a daily occurrence.
Dodge City was a flat area crisscrossed by numerous canals and small waterways — an area of around 23 square miles located 13 miles south of Da Nang, west of Highway One. Go Noi Island lay just south of Dodge City. The island became a stronghold and logistics base for hundreds (if not thousands) of Viet Cong (VC) and North Vietnamese Army (NVA) regulars of the R-20, V-25, and T-3 Sapper Battalions and the 36th NVA Regiment. Communist forces had the overwhelming support of local villagers, so recruiting VC fighters was never a problem.
The terrain of Go Noi Island was relatively flat, but the island’s several hamlets were linked together by thick hedges, well-concealed paths, and barriers to rapid movement. The net effect of hedges, pathways, and obstructions was a solid defensive network. U.S. Marines operating within the 7th Marine Regiment were knowledgeable of Go Noi Island, having conducted Operation JASPER SQUARE — with only minimal results. The Marine Corps standard for any endeavor exceeds “minimal,” which might explain the Commanding General’s overall unhappiness with the 7th Marines’ performance in Go Noi — so the 7th Marines would have to give it another try.
On the morning of 4 May 1968, Company E, Company G 2/7,  and a platoon of tanks crossed the Liberty Bridge onto the island. Their main task was to evacuate 220 civilians (mostly women, children, and the elderly) from Dai Loc, the district capital. For the first few days, the Marines experienced only light resistance. Afterward, 2/7 aggressed eastward along the main north-south railroad track, experiencing light but increasing resistance from local VC fighters.
Company A 1/7 relieved Company G 2/7 on 7 May. Company K 3/7 reinforced Mueller’s battalion on the morning of 8 May. In those four days, Marines killed 88 communists at the cost of 9 Marines KIA and 57 WIA. Around 1830 on 9 May, Marines sweeping west of the railroad track came under heavy small arms, machine guns, and mortar fire near the hamlet of Xuan Dai. The sudden assault resulted in one Marine killed and 11 wounded.
After air and artillery strikes, Marines pushed into the hamlet, killing an additional 80 communists. A few minutes later, a Marine Corps reconnaissance team (called a Stingray Team) noted the movement of 200 or so enemies moving southwest of Xuan Dai and called additional artillery and air strikes. The air strike set off a secondary explosion of unknown origin.
Over the next four days, Marines met with only token resistance and encountered no regular NVA units. This was a bit strange to Marine operations officers because earlier, the Marines discovered evidence of the 155th Battalion of the 2nd NVA Regiment. Colonel Mueller assumed the NVA battalion was only a temporary infiltration group rather than a regular infantry battalion.
It was at this time that Operation ALLEN BROOK was reoriented to an east-to-west sweep. On 13 May, General Robertson (Commanding General, 1stMarDiv) directed that India Company 3/27 reinforce Mueller’s battalion (2/7). Accordingly, Marine helicopters airlifted India Company to an LZ in the Que Son Mountains (north and overlooking Go Noi Island). On the morning of 14 May, India Company moved to a blocking position near the Ba Ren River, soon joined by additional companies of 2/7.
On 15th May the reinforced 2/7 reversed across the Liberty Bridge as part of a deception campaign, indicating that the Marines were abandoning Go Noi Island. Then, at 1800, Marine helicopters airlifted Echo Company 2/7 and Colonel Mueller’s command group out of the operational area. Lieutenant Colonel Roger H. Barnard, commanding 3/7, assumed command of the remaining forces assigned to ALLEN BROOK.
At midnight on 16 May, Barnard’s command group with Alpha Company 1/7, Golf Company 2/7, and India Company 3/27 recrossed the Liberty Bridge and moved in single file under cover of darkness. At some point in the early morning, Barnard repositioned his companies, two online with one in reserve, and continued moving southward in a search and destroy mission.
At 0900, 3/7 encountered a suspected NVA battalion in the hamlet of Phu Dong, some 4,000 meters west of Xuan Dai. Barnard’s battalion had disrupted a hornet’s nest of communists. Both forward companies walked into deadly small arms and machine gun fire. Barnard attempted to flank the communist defenders, but he didn’t have enough men for that maneuver. Not even Marine artillery or mortar fire could dislodge the stubborn NVA unit. Finally, massive air support (50 air strikes) dislodged the communists, and by early evening, Marine rifle companies were able to push the remaining enemy out of Phu Dong. But that didn’t happen without numerous Marine casualties.
Operating with Golf Company was a nineteen-year-old U.S. Navy Hospital Corpsman (Third Class) by the name of Robert Michael Casey from Guttenberg, New Jersey. Doc Casey distinguished himself by exhibiting extraordinary heroism as a field medic. As Golf Company moved into Phu Dong, they encountered overwhelming defensive fires from an estimated four hundred enemy, imposing a substantial number of casualties on the advancing Marines.
Casey unhesitatingly moved forward through the hail of bullets to render medical assistance to wounded and dying Marines. Within fifteen minutes, Doc Casey was hit four times by enemy rifle fire. Each time he was struck by enemy bullets, Casey refused to leave his post and continued to render medical assistance to “his Marines.” But U.S. Marines love their corpsmen; G Company Marines tried to convince Casey to fall back where he could receive medical treatment. Casey steadfastly refused, stating that he had Marines to treat. Casey continued to refuse evacuation until the Company Commander ordered him to withdraw. Casey moved to the rear, as ordered, but at his new location, Doc Casey continued to aid and comfort his wounded comrades. Then, hearing a Marine calling for help, he crawled to that individual and began administering medical treatment. It was at that time that Casey received his final wound and died.
Doc Casey’s unwavering courage, selfless concern for the welfare of his comrades, and steadfast devotion to duty brought great credit upon himself and the United States Navy. Doc Casey’s next of kin later received the posthumous award of the nation’s second highest combat decoration: the NAVY CROSS. More recently, the Marine Corps honored Doc Casey further by naming the Navy Branch Medical Clinic at Marine Corps Air Station, Iwakuni, Japan, in his honor (pictured right).
Golf Company had taken on a battalion-sized enemy organization and defeated them. In this fight, the Marines lost 25 dead and 38 wounded — one of whom was Doc Casey. After seizing the hamlet, the company commander discovered the evacuated headquarters of an NVA regiment and vast quantities of enemy supplies.
The following day, the Marines vacated Phu Dong to continue their sweep toward another hamlet named Le Nam. India Company 3/27 was the lead element of the column. Before mid-morning, India Company’s advance element walked into a concealed, well-placed ambush, offering almost no time for the Marines to fall back and reorganize for a coordinated attack.
The NVA positions were solid, preventing the other companies from assisting India Company. While India Company called for artillery and air strikes, Colonel Barnard put together a two-company air assault. Elements of Kilo Company and Lima Company initiated their attack around 1500, an effort that finally broke through the enemy’s main line of defense at about 1930.
Marine successes prompted yet another enemy withdrawal. By the end of the day, the Marines had lost another 39 KIA and 105 WIA. Private First Class Robert C. Burke (pictured above right), assigned to India Company as a machine-gunner, was later posthumously awarded the MEDAL OF HONOR.
The 3rd Battalion, 5th Marines, replaced 3/7, and the Commanding Officer 3/27 assumed operational control of ALLEN BROOK on 18 May 1968. At the same time Woodham took control of the operation, Colonel Adolph G. Schwenk, Jr. assumed overall operating authority from the 7th Marines. At that time, Woodham had only two rifle companies: Kilo and Lima Company. Company M was assigned security duties at Da Nang, and Company I was still attached to Barnard’s battalion.
Operation ALLEN BROOK continued until 27 May 1968. It was more or less a series of conventional battles against a well-entrenched, well-armed, and well-trained enemy force of North Vietnamese regulars. Casualties on both sides had been heavy, with Marine losses of 138 KIA, 686 WIA, and another 283 heat casualties (noting that the battle took place in 110-degree heat). Enemy losses were estimated to be around 600 killed and wounded. The deceptive tactics employed by the Marines resulted in defeating the enemy’s plan to launch a major offensive against the Da Nang airfield and surrounding area before the end of May.
- Kelley, M. Where We Were in Vietnam. Hellgate Press, 2002.
- Shulimson, J. U.S. Marines in Vietnam, 1968: The defining Year. HQMC Washington, D.C., 1997.
 Lieutenant Colonel Charles E. Mueller, Commanding.
 Information provided to me by Master Sergeant George Loar, Jr., USMC (Retired).
 PFC Burke was the youngest recipient of the Medal of Honor during the Vietnam War. At the time of his courageous action, he was 18 years of age.
 3/27 was under the command of Lieutenant Colonel Tullis J. Woodham, Jr.