Procedures serve to legitimate decisions independent of their content which may not convince all, especially the losing party (Niklas Luhmann). In procedures, parties are required to take up roles and they are expected to react to the arguments of others. In the end, having engaged voluntarily, the losing party learns that they must accept the decision. With his theory of procedure, Luhmann delivers a key concept for the understanding of societies which can no longer rely on a system of belief shared by all and which undergo rapid changes. The debate on Luhmann’s theory highlights differences between traditional ways of viewing procedures, namely only as a tool to arrive at a just decision, and a sociological analysis recognising wider functions of procedures. These include exhausting and socially isolating parties, binding them to decisions, and the public potentially developing trust in the system. Procedures are effective when they comply with general expectations of procedural fairness, later research accentuates Luhmann’s concept. This critical review shows how his theory can be amended.