The second reason that I was involved in the forecast of the Tet Offensive is that I and other NSA professionals had, since the early sixties, worked hard to identify North Vietnamese communications practices that preceded military attacks. We were so successful that we foretold every major North Vietnamese offensive from 1964 onward.
But neither the U.S. Military Assistance Command, Vietnam (MACV) nor the South Vietnamese prepared for the onslaught of the Tet Offensive. They were taken by surprise because they neither believed the forecast nor acted on it.
The irony of the Tet Offensive was that the North Vietnamese suffered a huge defeat but profited from the outcome. Their combat losses were enormous. The South Vietnamese populace did not arise in general insurrection, as the communists had hoped and expected. The troops of the Army of the Republic of Vietnam (ARVN) did not desert their posts. And the multiple attacks were repulsed.
But the North Vietnamese scored a political victory. The people of the U.S. had been told by their leaders that we were winning the war and that the North Vietnamese were near the end of their ability to fight. The Tet Offensive upended that premise. Opposition to the war grew rampant, leading to the withdrawal of U.S. forces from Vietnam in 1973 and the fall of Saigon in April 1975. My escape under fire as Saigon fell was but one of the many consequences brought on by the U.S. retreat from the war.
The memory of all these events overwhelmed me as I sat in the symposium and listened to the men I had worked with back then tell of our role in the Tet Offensive. The recollections were sad, but pride in our success in predicting the offensive leavened the bitterness.