When did the League require unanimous voting?

The League of Nations required unanimous voting for key decisions, particularly during its early years, to ensure that all member states agreed on significant issues. This requirement was established in its covenant adopted in 1919. However, the need for unanimous consent often led to inefficiencies and difficulties in decision-making, as it allowed any single member to block actions. Over time, this requirement was criticized and eventually modified in some instances to facilitate more effective governance.