This article looks at how a group of diverse economic experts tackled a major macroeconomic question and managed to reach a consensus conclusion. This was despite being confronted with limited data, embryonic general-equilibrium methodologies, and limited computing power. The realization, in the early 1960s, that the procession of nuclear weapons would shortly extend beyond the USA, Britain, France, and Russia led to increased fears of catastrophic global warfare. The economic concern with disarmament was along Keynesian lines, namely that reduced public expenditure on defense (“conversion”) could lead to a serious economic depression. The focus here is on a United Nations Consultative Group which had the remit of estimating the economic and social consequences of global disarmament. Using information from documents of the time, substantially supplemented with personal commentaries of committee members, both published and from archives, the paper examines how the committee managed to reconcile very divergent economic views to produce a unanimous report. These basic matters of political economy are as germane today as they were nearly sixty years ago. Indeed, probably more so with the challenges of sustainable development being added to those of global peace.