This analysis of the Anglo-French dispute over manpower resources in 1918, in the context of Germany's five Spring offensives on the Western Front, reveals the lack of effective and agreed policies. It examines from an alliance perspective a problem that has not before been so treated in print. After a brief account of the background to the crisis, the article discusses, first, the arguments presented in a French war ministry report on British manpower, and, second, the effects of the problems of transporting and deploying American troops. It goes on to examine some of the questions that were raised in consequence: industrial versus military mobilization; troop densities for a given length of line; and categories of fitness. Both British and French prime ministers spent much time and emotional energy in arguing about these matters. This was a dispute that was as bitter as it was pointless, because ultimately insoluble. Yet the efficient deployment of manpower resources was crucial to victory, and the dispute was dangerous for the maintenance of the coalition.