1992 Danish Maastricht Treaty referendum

The opt-outs are outlined in the Edinburgh Agreement and concern the EMU (as above), the Common Security and Defence Policy (CSDP), Justice and Home Affairs (JHA) and the citizenship of the European Union. With these opt-outs the Danish people accepted the treaty in a second referendum held in 1993.

The EMU opt-out meant Denmark was not obliged to participate in the third phase of the European Exchange Rate Mechanism, i.e. to replace the Danish krone with the euro. The abolition of the euro opt-out was put to a referendum in 2000 and was rejected. The CSDP opt-out originally meant Denmark would not be obliged to join the Western European Union (which originally handled the defence tasks of the EU). Now it means that Denmark does not participate in the European Union's foreign policy where defence is concerned. Hence it does not take part in decisions, does not act in that area and does not contribute troops to missions conducted under the auspices of the European Union. The JHA opt-out exempts Denmark from certain areas of home affairs. Significant parts of these areas were transferred from the third European Union pillar to the first under the Amsterdam Treaty; Denmark's opt-outs from these areas were kept valid through additional protocols. Acts made under those powers are not binding on Denmark except for those relating to Schengen, which are instead conducted on an intergovernmental basis with Denmark. The citizenship opt-out stated that European citizenship did not replace national citizenship; this opt-out was rendered meaningless when the Amsterdam Treaty adopted the same wording for all members. Under the Treaty of Lisbon, Denmark can change its opt-out from a complete opt-out to the case-by-case opt-in version that applies to Ireland whenever they wish.[5]

The June Movement, a Danish eurosceptic party and political organization was founded immediately after the referendum, and takes its name from the event.