In a referendum, voters in Sweden decide to join the European Union.
Since the introduction of parliamentarism in Sweden, six national referendums have been held. Legal provisions for referendums were introduced in 1922, one year after the adoption of universal suffrage. The Constitution of Sweden provides for binding referendums (concerning changes to the constitution), but all referendums held as of 2012 have been non-binding. The latest referendum, on adopting the euro, was held on 14 September 2003.
The Riksdag decides if a referendum is to be held, when it is held, and the wording of the issue on the ballot. Riksdag also interprets the results (sometimes the outcome is not clear cut, e.g. the nuclear power referendum of 1980). Ahead of the 1980, 1994 and 2003 referendums, all the parties with seats in the Riksdag promised to follow the outcome of the vote.Blank votes (to protest against the proceedings or the way the issue is framed, etc.) are considered valid in Swedish referendums and are tallied.
Since 1980, there have been legal provisions for binding referendums in questions concerning changes to the constitution and the adoption of international treaties that affect constitutional rights and responsibilities. For a binding referendum to happen, one tenth (i.e. 35) of the members of the Riksdag must demand it the first time the change is up for debate in the Riksdag. One third (i.e. 116) of the members must then support the referendum. The referendum then takes place during the next general election. The change to the constitution is rejected if a majority votes it down, and if the number of votes cast against the change number more than half of the votes cast in the general election. If this is not the case, the referendum becomes non-binding and the Riksdag decides whether to follow the outcome or not. Approval of change to the constitution in a referendum of this kind is never binding. As of 2017, no such referendum has been held.