One of the issues raised tangentially at the symposium was that our forecast of the Tet Offensive was not acted on. Speakers offered various theories about why.
My own sense is that army commanders in the field in Vietnam knew almost nothing about signals intelligence. Many didn’t even know such a thing existed.
Part of the cause for the ignorance was that NSA went to great lengths to keep even the existence of signals intelligence secret. For example, those of us who worked there then weren’t even allowed to say where we were employed, leading to the joke that NSA stood for “no such agency.” NSA had good reason to keep its work secret: once a target suspects that his communications might be subject to intercept, it’s easy for him to change his mode of communicating. When that happens, we lose the ability to intercept.
Another reason for the commanders’ ignorance was inadequate training in the army on the use of intelligence. I saw so often in my work with combat forces that officers in command brushed aside intelligence of all sorts in their determination to attack and win. The “can-do” spirit of the U.S. military is on the whole admirable, but sometimes it gets in the way of sensible procedure.
I never had the problem of commanders ignoring intelligence when I was working with the Marines. I don’t know why. I do know that Al Gray, the officer I kept running into all through my time in Vietnam and the man who saved my life when Saigon fell in 1975, had been a signals intelligence officer before he became a combat commander. And he had great influence with the Marines in Vietnam. They all knew him and respected him. He was a colonel when he rescued me during the fall of Saigon. He went on to become the commandant of the Marine Corps. And to this day, he spends time at NSA where he is esteemed and continues to advise on military exploitation of signals intelligence.