David Halberstam said this quote

“ Why did McNamara have such good figures? Why did McNamara have such good staff work and Ball such poor staff work? The next day Ball would angrily dispatch his staff to come up with the figures, to find out how McNamara had gotten them, and the staff would burrow away and occasionally find that one of the reasons that Ball did not have comparable figures was that they did not always exist. McNamara had invented them, he dissembled even within the bureaucracy, though, of course, always for a good cause. It was part of his sense of service. He believed in what he did, and thus the morality of it was assured, and everything else fell into place. It was all right to lie and dissemble for the right causes. It was part of service, loyalty to the President, not to the nation, not to colleagues, it was a very special bureaucratic-corporate definition of integrity; you could do almost anything you wanted as long as it served your superior. ”