Electoral system
Electoral rules place limits on suffrage and candidacy. Most countries's electorates are characterised by universal suffrage, but there are differences on the age at which people are allowed to vote, with the youngest being 16 and the oldest 21 (although voters must be 25 to vote in Senate elections in Italy). People may be disenfranchised for a range of reasons, such as being a serving prisoner, being declared bankrupt, having committed certain crimes or being a serving member of the armed forces. Similar limits are placed on candidacy (also known as passive suffrage), and in many cases the age limit for candidates is higher than the voting age. A total of 21 countries have compulsory voting, although in some there is an upper age limit on enforcement of the law. Many countries also have the none of the above option on their ballot papers.
Referendums by country
Originally none of the Bundesländer (federated states) had provisions for a general binding referendum ("Volksentscheid" "people's decision"). Only Hesse and Bavaria have a mandatory binding referendum on changes to the state constitution. However, most states have a form of non-binding ballot question ("Volksbefragung" "people's inquiry") which has rarely been used - the most important one had been the Saar Statute referendum, 1955. General forms of direct democracy were first introduced in the communities with facultative ballot questions ("Bürgerbefragung" "citizens inquiry") and public initiatives ("Bürgerbegehren" "citizens request") that are both non-binding. In some areas, this has been expanded into a binding referendum type ("Bürgerentscheid" "citizens decision") but almost universally facultative. In some states, there is a general right on state popular initiatives ("Volksbegehren" "people's request") which was used in Hamburg to push the state government to pass a law on a facultative binding state referendum ("Volksentscheid") in 2007.