The Author compares two different systems of collective decision: voting and deliberating. In order to illustrate the different deliberating systems, the author refers to two concrete cases: the verdicts of the Italian Constitutional Court and the debates that yielded the recent UE constitutional chart prepared by the Convention. Deliberative decisions, or by consensus, are taken by politically non-responsible organs. These, as such, do not rely upon the mechanism of the majority vote, which is, on the contrary, appropriate for institutions politically responsible to voters, but their decisions, in order to become authoritative, must result from a deliberation that includes all viewpoints.