Recent work on socio-technical controversies (conflicts) have brought out the emergence of a new model of political decision. In this model decisions are reversible and adopted at the end of an open debate that allows the groups concerned to intervene on the merits of technical options. The article shows the gradual setting up of a model for nuclear waste. It explains how and why the idea of a reversible political decision has been imposed and suggests how it might be transposed to other sectors. only subscribers can see the full article