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.
Secret ballot
The United Nations Convention on the Rights of Persons with Disabilities which entered into force in 2008 assures secret ballot for disabled voters. Article 29 of the Convention requires that all Contracting States protect "the right of the person with disabilities to vote by secret ballot in elections and public referendums". According to this provision, each Contracting State should provide for voting equipment which would enable disabled voters to vote independently and secretly. Some democracies, e.g. the United States, the Netherlands, Slovenia, Albania or India allow disabled voters to use electronic voting machines. In others, among them Azerbaijan, Canada, Ghana, the United Kingdom, and most African and Asian countries, visually impaired voters can use ballots in Braille or paper ballot templates. Article 29 also requires that Contracting States ensure "that voting procedures, facilities and materials are appropriate, accessible and easy to understand and use." In some democracies, e.g. United Kingdom, Sweden and the United States, all the polling places already are fully accessible for disabled voters.