 As the Maastricht Treaty could only come into effect if all members of the European Union ratified it, the Edinburgh Agreement, negotiated in the months following the referendum, provided Denmark with four exceptions which eventually led to Denmark ratifying the Maastricht Treaty in a 1993 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.