The Vietnam War-era U.S. military unit MACV-SOG had two meanings, one unclassified, the other classified. The unclassified and nondescript meaning was Military Assistance Command, Vietnam-Studies and Observation Group. The classified meaning was Military Assistance Command Vietnam-Special Operations Group, responsible for covert operations against North Vietnam. Both terms refer to the same operations unit.
At the May 1963 Pacific commanders' conference, decision were made to conduct covert operations. First, of course, there needed to be a unit in Vietnam to carry out these mission. MACV-SOG started to appear on unclassified organizational charts. It was formally established on January 24, 1964. 
Previous CIA agent programs for the North were gradually moving under MACV control — although SOG always had an Army commander, Air Force deputy commander, and CIA officer in the next highest role. The classified command history states that all operations were joint with South Vietnamese counterparts, generally called Strategic Technical Directorate (Vietnamese: Nha Ky Thuat), although unofficial sources say that MACV-SOG often considered STD as penetrated by North Vietnamese intelligence, and was trusted only to a limited extent. There may have been independent CIA operations working with other Vietnamese groups.
The U.S. had a shortage of covert operators, with Asian experience. in general. ironically, Assistant Secretary of State Roger Hilsman, who had been a guerrilla in Asia during the Second World War, was forced out of office on February 24. George Ball, with the concurrence of Secretary of State Dean Rusk, took great pride in firing him. 
It ran operations inside and outside the South. Operations into Cambodia were codenamed SALEM HOUSE (previously DANIEL BOONE), operations into Laos were PRAIRIE FIRE (previously SHINING BRASS), NICKEL STEEL actions were in the Demilitarized Zone, and there were numerous compartments dealing with operations in and against North Vietnam.
SOG operations could require incredibly complex approval, up to and including presidential level. 
SOG's initial organization
The first chief of MACV-SOG was COL Clyde Russell, who had been a WWII paratroop officer who transferred to Special Forces at a rather high rank, and without experience of covert action against targets in enemy areas. Paratroopers do jump behind enemy lines, but assembling into regular units as soon as possible, fighting intensely and overtly, but expecting conventional forces to link up with them within a few days. The first commander of the airborne operations section was a Special Forces lieutenant colonel named Edward Partain, whose experience had been planning guerrilla, not intelligence, networks, behind Soviet lines. 
Russell faced problems of organizational doctrine as well as military politics. U.S. doctrine for offensive guerrilla operations, then as now but far less developed at the time, called for the formation of a Joint Unconventional Warfare Task Force (JUWTF), with components from each of the services. The argument for keeping distinct service identities was better integration with the regular military. Jack Singlaub, to become the third commander of SOG, argued that special operators needed to form their own identity; while today's United States Special Operations Command has components from all the services, there is a regional Special Operations Component, alongside Army, Navy, Air Force, and Marine Components, in every geographic Unified Combatant Command. Today, officers from the special operations community have risen to four-star rank, including Chairman of the Joint Chiefs of Staff, but special operators were regarded as outcasts, unlikely to rise high in rank, during the Vietnam War.
South Vietnamese covert operations
Another challenge was working with the South Vietnamese counterpart of SOG, called the Strategic Technical Directorate (STD). Originally, SOG was to advise STD in conducting its own operations. In practice, MACV-SOG ran its own operations, sometimes with Vietnamese under its direct command, an exception to the relationships between U.S. and Vietnamese forces. There was considerable, sometimes justifiable, concern that STD may have been penetrated by Communist agents. Details of STD, some from unofficial sources such as the son of its Vice Director, Colonel Ngo The Linh, are only beginning to become available and the situation is being reassessed. 
Building the first operational effort
Not only was there a problem in finding officers with marginally relevant qualifications, the standard tour of duty in Vietnam was one year — about the time it took an officer, inexperienced with this type of covert operation, to gain a reasonable understanding of the mission. Russell, in May 1965, passed command to an unusually well qualified officer, Donald Blackburn. Blackburn, as a junior officer when the Japanese conquered the Philippines, refused to surrender, and built a major and effective guerrilla organization, working well with both Americans and Filipinos. At the end of the war, he was the youngest full colonel in the United States Army, which was not quite sure what to do with a combat-proven 29-year-old colonel. As an indication of the contemporary career dead end that was special operations, twenty years later, he was still a colonel, with the longest time in grade of any colonel in the Army.
SOG, at this point, had five tightly compartmented operational mission elements targeted against North Vietnam, under the overall code name FOOTBOY; as with any organization, they restructured over time:
- TIMBERWORK: Long- and short-term intelligence agent insertion, with a strategic deception subcompartment known as FORAE
- PLOWMAN: Psychological and paramilitary operations by naval forces
- Other black propaganda, which was usually run by the senior CIA officer, and included such things as the creation of a nonexistent resistance movement in the North, called the Sacred Sword of the Patriots League, which was intended to encourage the expected paranoia of North Vietnamese internal security and send them into chasing phantoms
- SHINING BRASS: cross-borer reconnaissance into Laos, renamed DANIEL BOONE when Cambodian penetrations were authorized
- MIDRIFF: air support for the other three compartments, covertly operating over North Vietnam, Laos, and Cambodia
Besides MIDRIFF, there were other support elements for special supplies, communications, etc.
While Westmoreland respected Blackburn's combat experience, Westmoreland talked to generals, not colonels. Blackburn was to brief him once during his year of command. In Vietnam, special operators had far lower ranks than was warranted by their responsibilities. For example, the commander of the 5th Special Forces Group controlled irregular troops in the numbers of a regular army division, a command for a two-star major general. The Special Forces group commander was also a colonel. Even today, while special operations has enormously more prestige and specialists can rise to the highest ranks, in a geographical Unified Combatant Command, the Army, Navy, Air Force and Marine component commanders are three-star lieutenant generals, while the special operations component commander is a colonel or one-star brigadier general.
Agent and deception operations
According to the original PACOM plan, the purpose of MACV-SOG's Airborne Operations Group designated OP34 agent insertion was to build resistance networks, as opposed to the fictitious Sacred Sword of the Patriots League that was a separate black propaganda operation involving naval operations and clandestine radio. The authorized missions were, through 1966, intelligence collection, sabotage, and psychological warfare. After 1966, sabotage and psychological operations were made secondary to direct reconnaissance on major roads leading to the Ho Chi Minh Trail, as well as establishing civilian contacts for intelligence collection.
With both limited information gathered and a serious concern about compromise, the mission again changed, to the insertion of short-term "strata" special reconnaissance teams. Since no long-term agent team was ever successfully infiltrated and exfiltrated, the short-term surveillance missions were another option. Precisely due to the likelihood of capture and doubling of the long-term teams, another mission, codenamed FORAE, was set up to send deceptive information through unwittingly redoubled agents.
At the end of 1968, therefore, the Airborne Operations Group had three branches:
- OP34A: agent operations
- OP34B: strata operations
- OP34C: diversionary operations
Deception in the MACV-SOG context differed significantly from Second World War programs of the London Controlling Section (LCS). Those programs were intended to cause specific enemy decisions or actions, rather than just be confused and waste effort, the goal of FORAE.  Under Plan BODYGUARD, there were a series of LCS operations, all to convince the Germans that the cross-channel invasion would strike anywhere except Normandy. FORTITUDE SOUTH was the deception that the invasion was to cross the English Channel at its narrowest point, and land at the Pas de Calais. This seems to have been accepted by the Germans, and nothing would have been harmed if they decided other deceptive hints, such as FORTITUDE NORTH indicating Norway would be invaded, was seen as a deception. Characteristic of these WWII programs is that they started with a conclusion the LCS wanted the enemy to reach, and then selected means to lead him in the desired direction.
FORAE programs included:
- BORDEN, which recruited ordinary NVA prisoners of war and sent them back as minimally trained SOG agents, whom SOG expected to be captured, and make the North suspect there was a resistance movement that these agents were to support.
- URGENCY, in contrast, did not recruit potentially cooperative agents, but sent hard-core PAVN members, convinced of their ideology, back in such a way that the Northern security organization would believe that actually loyal individuals had been turned. In more recent tradecraft, such programs have been called "spay, neuter, and release".
- OODLES, which did not actually send agents into the North, but gave the impression that it was doing so. It would drop personnel parachutes weighted with ice, which would quickly melt, but show the signs to North Vietnamese security of a successful agent drop. Radio transmitters that would send apparently coded messages from agent teams in operation. Also, BORDEN and URGENCY personnel would be told that they were meet with nonexistent OODLES teams, in the hope they would report this to their interrogators.
The existence of three units that conducted cross-border reconnaissance, and some direct action has been mentioned much more widely than was MACV-SOG: Special Operations Augmentation Command and Control units. While these were classified programs, the first level of cover implied that they were operations of the 5th Special Forces Group. In reality, they were actually under OP35, the Ground Studies Branch of SOG.
- North, based in Da Nang, aimed at Laos and North Vietnam.
- Central, based in Kontum, responsible for the triangular meeting of Vietnam, Laos and Cambodia.
- South, based in Ban Me Thuot and targeted on VC-dominated areas of the South, as well as Cambodia
MACV-SOG carried out special reconnaissance in Laos and Cambodia, in which they were to avoid direct combat; they were there either to collect intelligence for the moderate term, or to give targets to air strikes, especially by B-52 heavy bombers using ARC LIGHT tactics. Under some circumstances, the political situation was such that the penetration could not be compromised.
"If I decide that there’s no way we can effect your rescue [in Cambodia], I’ll order the gunships to fire at you to prevent the enemy from getting their hands on you. I can’t risk having any of the [recon] teams compromised if they take you alive."
The recon team, in such a situation, might only have choices among bad options. United States Army Special Forces personnel in Southeast Asia have spoken, informally, of unwritten agreements among team members: if they were captured by the enemy, they would rather be killed by friends than go into a long-suffering captivity that might, in any event, be fatal.
MACV-SOG and the Gulf of Tonkin incident
On 9 September 1963, the Joint Chiefs of Staff (JCS) approved CINCPAC OPLAN 34-63, which called for MACV and the Central Intelligence Agency (known as CAS), Saigon to provide advice and assistance to the GVN in certain operations against NVN. Phase I of the plan was to consist of "Psychological Operations"; Phase II of "Hit and Run Attacks." The latter included "amphibious raids using Vietnamese UDT/SEAL Team, Rangers, Airborne, and Marine units against selected targets south of the Tonkin Delta having little or no security." Apparently, the plan was not forwarded to the White House by SecDef. 
While the attacks on the DESOTO patrols were explained as attacks on vessels carrying out free passage, and had not provoked the DRV other than to sail inside its claimed 12 mile limit (the US respected a traditional 3 mile limit, "In fact the United States at the time was carrying out a program of covert naval commando attacks against North Vietnam and had been engaged in this effort since its approval by Johnson in January 1964."  The NSA report also said the Maddox had first fired warning shots.
There almost certainly was a North Vietnamese attack, on August 2, on the single-destroyer DESOTO patrol being conducted by the USS Maddox'. It is still unclear if what became known as the Gulf of Tonkin Incident was meant as retaliation for the prior 34A raid, or if they regarded the Maddox as a potential attacker, or simply wanted to increase pressure on the U.S. In any event, the President ordered a second destroyer, the USS C. Turner Joy, to join the Maddox.
34-A forces carried out another raid on North Vietnam during the night of August 3/4, when the U.S. destroyers were beginning their run back up the Tonkin Gulf. If Hanoi was responding to the first raid, a second one furnished an equivalent reason to act against the reinforced DeSoto Patrol.
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- Military Assistance Command, Vietnam Command History Chronology - 1964
- Mullholan, Paige E. (July 8, 1971), Oral History Interview with George W. Ball, Interview 1, p. I-4
- SOG-1970, p. B-13
- SOG-1970, p. B-16
- SOG-1970, p. B-19
- SOG-1970, p. xiii
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- Shultz, p. 49
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