Requirements of participation in direct democratic procedures

Several institutions of direct democracy – primarily popular initiatives – are widespread interpreted as the strongest weapon of the distrustful people against the political elite. From this point of view one of the most important questions of these institutions’ design is the minimum number of the voters enough for initiating a referendum. Irrespectively of the sources of initiative – constitutions, voters, political parties or governments – it is also enlightening how do the national legal systems handle the decreasing level of political participation. How do they determine referendum’s turnout requirements: are there quorums, quotas of valid votes enough for a legally binding result?