Foreign Relations of the United States, 1964–1968, Volume IV, Vietnam, 1966

233. Memorandum From Secretary of Defense McNamara to the Director of the Defense Communications Agency (Starbird)¹

Washington, September 15, 1966.

SUBJECT

• Infiltration Interdiction System for Vietnam

An infiltration interdiction system, to stop (or at a minimum to substantially reduce) the flow of men and supplies from North to South Vietnam, is to be designed, produced, and put in place in South Vietnam and Laos as a matter of highest priority. You are hereby named Director of Joint Task Force 728 to achieve the objective of having the system installed and in operation by September 15, 1967. The present concept, which may have to be modified as your work progresses, is summarized on the attached sheet.²

To make this system work: There will be required experimentation and further development for such features as foliage penetration, moisture resistance, and proper dispersion of gravel; development of a better acoustic sensor than currently exists; aircraft modifications; possible modifications in BLU–26B fusing; refinement of strike-navigation tactics; and total system tests. Production of components will have to be increased, personnel will have to be trained, a unit and command structure to operate and supply the system will have to be created, and a doctrine for its operation will have to be developed. Communist infiltration practices and the location of civilian populations will have to be studied. Political groundwork will have to be laid. Public relations questions will have to be addressed.³ Furthermore, to keep ahead of countermeasures, new components of the system and new tactics will have to be under development even before the first generation system is installed.

In carrying out your duties as Director of the Joint Task Force, you will report directly to me and are authorized direct contact with the JCS, the Military Services, and subordinate organizations. Dr. Foster (DDR&E) will represent me as necessary to assist you in the achievement of your assignment. Implementation will involve political affairs and matters of concern to ISA, the State Department and foreign governments; you should therefore keep Mr. McNaughton (ASD/ISA) fully informed and call on him for assistance as necessary in those areas. I expect you to make use of an advisory group of non-governmental experts, including Dr. George Kistiakowsky. You will keep the Chairman, JCS fully informed as to the status and progress of your work.

You should immediately establish a project office and submit to me by September 29 an outline of a program for carrying out your task. This program should include the approximate time schedule you plan to meet over the next twelve months; preliminary estimates of your needs in personnel, equipment and facilities; and an initial plan of your proposed organization.

The existence and operations of the Joint Task Force should be kept confidential.

You are to feel free to call on me as necessary for resources, guidance, decisions, and any other assistance.

Robert S. McNamara

Attachment

CONCEPT FOR INFILTRATION INTERDICTION SYSTEM FOR VIETNAM

The system would have two different parts—one part designed against foot traffic and the other against vehicles. The location for the anti-foot-traffic part would be in South Vietnam along the southern edge (outside) of the DMZ to the Laotian border and then on westward, north of Tchepone, to the vicinity of Muong Sen. Except for the portion nearest the sea, the area involved is virtually unpopulated and the terrain is quite rugged. The location for the anti-vehicle part of the system would be the area, about 100 kilometers north-south and 40 kilometers east-west, covering the road networks in eastern Laos from north of Mu Gia Pass to south of Route 9. The eastern end of the anti-foot-traffic part would be a wide ground barrier of mine fields, concertina, fences, sensing devices, patrols and air-mobile troops. The remainder of the anti-foot-traffic system and all of the anti-vehicle system would be effectuated entirely by air actions.

The first generation of the anti-foot-traffic part of the interdiction system would involve a combination of non-sterilizing gravel mines for area denial off the trails where sweeping would be difficult, gravel mines plus “button bomblets” on the trails to harass and to signal acoustic sensors, acoustic detectors to pinpoint explosions caused by infiltrators, and Sadeye/BLU–26B clusters for saturation attacks on areas where infiltrators were detected. The mined area—which would constantly be reseeded—would encompass a strip about 100 by 5 kilometers. The sensor patterns, laid through and around this field would be monitored 24 hours a day by patrol aircraft, which could call in strike aircraft on a few momentʼs notice.

The first generation of the anti-vehicle system would consist of acoustic detectors, supplemented by gravel mines, distributed along all truckable roads in the zone; 24-hours-a-day monitoring by patrol aircraft; and strike aircraft using SADEYE prepared to respond to signals that trucks had been located.

The cost of both parts of such an initial system has been estimated to be about $800 million per year, and the key requirements to be approximately 20 million gravel mines per month, 25 million button bomblets per month, 10,000 SADEYE/BLU–26B clusters per month, 1600 acoustic sensors per month, 70 appropriately equipped PO2V patrol aircraft, 20 mine-dispensing C–123s, 500 strike sorties per month, and sufficient photo reconnaissance to cover 2500 square miles a week.

1. Source: Washington National Records Center, RG 330, OASD/ISA Files: FRC 70 A 4443, VIET 385 BARRIER. Secret.
2. The concept summarized in the attachment was drawn from the study, “Air-Supported Anti-Infiltration Barrier,” August 1966, prepared by the Jason Division of the Institute of Defense Analyses. (Johnson Library, National Security File, Country File, Vietnam, 2D, Barrier) For background information on the study, see Document 163 and The Pentagon Papers: Gravel Edition, vol. IV, pp. 115–123.
3. Fosterʼs memorandum for the record of a meeting on the barrier, September 6, attended by McNamara, McNaughton, Kistiakowsky, and other members of the Jason study team, indicates that “note was taken of a number of serious non-technical problems, including possible added dangers to Laos and Thailand; the CINCPAC, MAC–V and Ambassador Sullivanʼs attitudes; and the possibility of premature leakage to the press.” (Washington National Records Center, RG 330, OASD/ISA Files: FRC 70 A 4662, VIET 385 BARRIER)