August 4, 1964

Robert McNamara:

On August 4th, it was reported another attack occurred. It was not clear then that that attack had occurred. We made every possible effort to determine whether it had or not. I was in direct communication with the Commander-in-Chief of all of our forces in the Pacific (CINCPAC) by telephone several times during that day, to find out whether it had or hadn’t occurred. He had reports from the commanders of the destroyers on the scene: they had what were known as sonar readings — these are sound readings. There were eyewitness reports. And ultimately it was concluded that almost certainly the attack had occurred. But even at the time there was some recognition of a margin of error, so we thought it highly probable but not entirely certain. And because it was highly probable — and because even if it hadn’t occurred, there was strong feeling we should have responded to the first attack, which we were positive had occurred — President Johnson decided to respond to the second [attack]. I think it is now clear [the second attack] did not occur. I asked [North Vietnamese] General Giap myself, when I visited Hanoi in November of 1995, whether it had occurred, and he said no. I accept that.