OSI at 75: A Contemporary Analysis of the Area Source Program in Vietnam

  • Published
  • By Robert Vanderpool
  • OSI Command Historian

Air base defense was one of the Office of Special Investigations’ highest priorities during the Vietnam War. The following analysis regarding air base defense and the establishment and evolution of the area source program to collect information in support of this mission was produced by the Office of Special Investigations District 50 Headquarters in 1969:

The Challenge

The nature of the Vietnam War requires emphasis on the collection of ground combat intelligence and counterintelligence information. The war, in many respects, is an “Intelligence War.” This is due to the nature of Communist activities in the Republic of Vietnam, where the Communists are waging an unconventional war in which overt military action is but one aspect of the total effort. Espionage, sabotage, terrorism and subversion are typical tools used by the enemy to gain his objectives. It is by these means that the enemy prepares for, assists, and exploits his military activities against the Republic of Vietnam and Allied forces. There is no firmly drawn battle line at which opposing forces peer at each other over the parapets of the enemy anywhere – en as well near Allied military installations.  The nature of this war, therefore, has posed problems of security and defense unique to U.S. forces, particularly the U.S. Air Force. To successfully meet this new situation, OSI has found it necessary to adjust its attitudes, methods, and mission definitions.  

The OSI Response to the Challenge

The most sizeable contribution OSI is making to the Vietnam War effort is the systematic and timely collection, analysis and dissemination of information required for planning air base defense measures. Today, the air base commander in the Republic of Vietnam has a continuing problem that only rarely concerned his counterpart of earlier wars. This is the threat of a frontal assault on his base perimeter and/or long range artillery type attack. The peculiarities of a situation in which the entire country is a combat zone and the enemy, if he chooses, a virtually indistinguishable part of the indigenous population has led to the conclusion that within such an environment, classic differences between counterintelligence and “positive” intelligence are irrelevant. OSI’s mission in Vietnam has been augmented with the requirement to collect and disseminate information on all enemy activities which could adversely affect the security and combat capability of installations hosting U.S. Air Force units.

The Essential Elements of Information

What is needed, then, is information which may lead to better defensive measures at a given air base. The information needed by the air base commander includes enemy plans to initiate hostilities; the capability of enemy forces within 30 kilometers of each installation to launch assaults or other military action against the base; and the strategy, tactics, and modus operandi of enemy units regardless of location. The 30 kilometer range is an arbitrary but flexible one based on the currently accepted maximum range of enemy ordnance, plus staging areas and their approaches. 

The Information Collection Apparatus

In order to collect the required information, a new source system was developed. As currently configured, the area source program is two-pronged. One prong is the bilateral effort in which OSI provides training, advice, and material support and limited funds to the Vietnamese Air Force Security Division, which, in turn, recruits and manages sources among Vietnamese nationals. The other prong of the area source program is the unilateral effort.  In the unilateral system, OSI controls the operations without reference to other Allied agencies. The sources are controlled either by Vietnamese nationals employed by OSI who act as couriers between the net chiefs and OSI or by OSI agents who control the net chiefs directly. 

Establishing a bilateral source system with a Republic of Vietnam counterpart agency requires the following steps:

                        1.) Selection and establishment of a working relationship with the agency.

                        2.) Training and support of the agency source handlers.

                        3.) Spotting, vetting and recruitment of area source program sources.

                        4.) Levying essential elements of information requirements on the sources.

                        5.) Establishment of communications channels.

                        6.) Implementation of funding procedures.

                        7.) Implementation of source management procedures.

Establishing a unilateral program requires somewhat different initial steps: Spotting, vetting and recruitment of Vietnamese civilian source net handlers.  These may include, but not be limited to, OSI employees, civilian employees of an air base, or civilians with a wide range of acquaintances and/or travel opportunities. The remaining steps are essentially the same as those of a bilateral operation.

Once in operation, a net, either bilateral or unilateral, consists of numerous sources. At present time, the area source program has approximately 420 carded sources and sub-sources and an estimated 2000 un-carded sub-sources. This body of sources is constantly being improved through the elimination of “deadwood” and the addition of new sources, many of whom eventually are upgraded from uncarded subsources. As might be expected, the size and productivity of the area source program varies from base to base.

The Dissemination of Information

Even the best of information is of no value unless it is accurately and expeditiously furnished to command and other authorities having need for it and in a position to react to it.  For this reason, every one of the 1,300-1,600 items of information reported each month through the area source program is disseminated within hours of its acquisition to the appropriate base commander, wing intelligence officer, other U.S. Air Force authorities, U.S. Army, U.S. Navy, Marine Corps, Vietnamese and other Allied elements with reaction capabilities in a given area.

This information is distributed locally by means of the raw information report. At selected intervals, the raw information reports submitted by each OSI detachment are consolidated, carefully researched against information provided by other members of the intelligence community and analyzed to determine any patterns and trends of enemy activity that may prove significant to future events and published in a Department of Defense Intelligence Information Report. Although this process of consolidation, research and analysis requires a certain period of time, it provides a perspective and frame of reference which may not be readily perceived at the operational level in the field. As a rule, the Intelligence Information Report is published within five to eight days of the most recently dated information it contains.


In the words of a former science advisor to the U.S. Military Assistance Command, Vietnam, “…an increased local OSI intelligence operation is probably the most cost-effective means of achieving a significant and rapid upgrading of our air base defense posture.”  The area source program has been and is an effective producer of low-level, passive observation-type ground combat intelligence information. Through it, interested authorities are furnished timely information concerning the identification of hostile forces in the vicinity of an air base, their location, strength, armament, equipment, current activity, direction of movement (if any), and frequently stated intentions of a general nature. The area source program is normally not productive of specific, detailed plans for hostile offensive action, the information most vitally needed for appropriate command reaction. In recognition of this inherent weakness of the area source program, OSI is currently endeavoring to meet this need by utilizing existing area source program resources for the purpose of identifying those elements of the Viet Cong infrastructure presenting the most immediate threat to U.S. Air Force installations. Once identified, these Viet Cong cadre will be the targets of operations designed to penetrate the local policy making levels of the opposition for the purpose of obtaining definitive information on specific enemy plans for offensive action directed against the U.S. Air Force in the Republic of Vietnam.

Editor’s Note: OSI at 75 is an installment of OSI’s year-long commemoration of its 75th Anniversary Year based on the theme: “Inspired By Our Past – OSI’s Future Starts Today.”