Intelligence Ignored

PAVN 122mm artillery battery goes into action on the Kon Tum front. (Joel D. Meyerson, Images of a Lengthy War. Washington DC: US Army Center of Military History, 1986.)

By W.R. (Bob) Baker
Originally published in Small Wars Journal, 02/01/2023

As the Easter Offensive of 1972 was the precursor to the signing of the Paris Peace Accords of 1973, there were two occasions where the United States could and should have moved against North Vietnam earlier but didn’t.

The first time occurred prior to the invasion of South Vietnam by the North Vietnamese Army (NVA), which began of March 30, 1972, was when William Stearman, a career Foreign Service member who went over to the National Security Council (NSC), put together a small sub rosa group before the Easter Offensive. This group was composed of NSA, CIA, and DIA members, as well as Dr. Steve Hosmer of RAND and Dr. Stearman. Using Open-Source Intelligence (OSINT)—the Hanoi newspapers—they had they first inkling of what was to be the Easter Offensive in the fall of 1971.

They found that North Vietnamese men who were previously exempted (both skilled and physically unfit, Chinese, and Montagnards who didn’t speak Vietnamese) were all being conscripted in North Vietnam, they looked at seasonal weather patterns, and “communications shifts,” all of which brought them to the conclusion that the date of the invasion was to be somewhere around 10 days before it actually occurred, which was March 30th. This analysis was passed to Henry Kissinger’s deputy, General Alexander Haig. “I wrongly passed this on to Al Haig who seems to have ignored it, since our generals were caught by surprise,” Stearman wrote.

The second occurrence happened shortly afterward.

DIA (the Defense Intelligence Agency) noticed a large increase in men, materiel, and new unit traffic headed south along the Ho Chi Minh Trail. Sound, heat, urine, and vibration sensors were placed along the Trail to detect movement of troops and trucks. Colonel Peter Armstrong, USMC, wrote, “Our estimate was based on hard intelligence, and as the intelligence business is a very competitive one, I also enjoyed the fact the DIA was first on the street with the new estimate.”

The North Vietnamese invasion of the South through the Demilitarized Zone and Laos. (Courtesy W.R. Baker)

The 571st Military Intelligence Detachment (the only US intelligence unit still operating in South Vietnam’s I Corps) however, never received anything from DIA, nor any reference to their estimate. COL Armstrong also wrote that, “South Vietnamese units, while well aware of the impending offensive, were not prepared for the enormity of the Communist’s thrust directly through the DMZ.” If they were so well aware, why did US Ambassador (to South Vietnam) Ellsworth Bunker, General Creighton Abrams (MACV commander), and Major General William E. Potts (his J-2, Intelligence officer) all leave the country and why did two ARVN regiments below the DMZ turn off their comms and hit the road to swap positions on the very morning of the Easter Offensive of 1972? None of which could possibly indicate any sign of “high levels of awareness” or warning.

Surprisingly, the full extent of the invasion only became evident four days later. President Nixon “insisted that it was impossible for the North Vietnamese to have assembled three divisions and support facilities without the Pentagon’s knowing about it. Laird, so the President made clear, had deliberately withheld the information.” Secretary Laird must not have remembered COL Armstrong’s briefing he received in January 1972.

Members of the South Vietnamese 20th Tank Regiment ride a captured North Vietnamese T59 tank south of Dong Ha during the Easter Offensive. (U.S. Army Center of Military History)

The 571st knew something was going to happen from the information our agents were sending to us. This Human Intelligence allowed us to translate their information into exact locations and to correctly surmise their initial intentions—few headquarters (both in-country and out) listened until the NVA invasion began. For instance, one of the three NVA divisions was positioned west of Hue three weeks before one division entered South Vietnam from the Trail as another division and multiple independ