The South Vietnamese, America's allies, were cavalier with numbers. Hence his frustration with them. The enemy Vietcong made each person count. After saturation American bombing in 1965, Mr McNamara found they were still getting 200 tons of supplies a day along the Ho Chi Minh trail, and had scattered the country with a secret stash of oil in hundreds of 55-gallon drums. The importance of tiny peasant efforts to the health of a nation struck him again when, from 1968-81, he headed the World Bank, shifting its focus and its money to rural development.

He saw himself as an "enlightened rationalist", and looked the part, with his oiled hair and boffin's glasses and strict attention to time. If business had not called, in the shape of Henry Ford, and if public service had not called later, with John Kennedy asking him to take first Treasury and then Defence, he might have stayed at Harvard teaching economics. Not long after joining Kennedy's White House, he drew the president a little graph of his authority: power on the vertical axis, his putative two terms on the horizontal, with effectiveness a declining line between them. Sadly, his horizontal axis proved too long.

It was often his fate to be saddled with bad numbers. At Ford it was the Edsel, a clunker-car with contrasting tail-fins and unlovely squarish styling, which sold only 68,045 in 1958, its first year, and 47,496 in its second, until he killed it in favour of the smaller, cheaper Falcon. At the Pentagon, where he arrived in 1961 with 99 topics for evaluation, he found a budget of $55 billion that had to be trimmed by bringing in systems analysis and five-year plans. He forced cuts in bases and procurement on the outraged joint chiefs, only to find some money mysteriously restored again.

... contd.