Unemployment exacts a high cost to its victims, not only in lost income, but also in terms of quality of life (insecurity, depression, abandoned families, divorce, suicide and poorer health). It also exacts a high cost to society in terms of lost output, foregone tax revenue, depreciating human capital, and increased costs of welfare, crime and health care. Yet modern wealthy societies have, principally for the sake of price stability and to avoid the budget costs of a full remedy, chosen to tolerate a substantial level of permanent unemployment. This article explores the moral conditions of this social choice and its rationality in terms of social welfare. It makes and develops support for two claims: society’s tolerance of involuntary unemployment is morally wrong, and it is socially and economically irrational. It concludes that government should guarantee employment by serving as employer of last resort and where appropriate provide for retraining.