 We have known this from the beginning.But the discouraging truth is that, as was the case in 1961 and 1963 and 1965, we have not found the formula, the catalyst, for training and inspiring them into effective action".Because the effects of Operation Rolling Thunder were more easily measured than with the ground war, McNamara was especially troubled by the revelation that the bombing offensive had not caused the collapse of North Vietnam's economy as predicated.