Issues in relation to which referendums are optional at the national level

Denmark
- Adoption of international treaties
- Legislative bills
Denmark, Constitution 1953, accessed 24 September 2019
Section 42.
1. Where a Bill has been passed by the Folketing, one-third of the Members of the Folketing may within three week-days from the final passing of the Bill request of the President that the Bill be subjected to a Referendum. Such request shall be made in writing and signed by the Members making the request.
2. Except in the instance mentioned in subsection 7, no Bill which may be subjected to a Referendum, confer subsection (6), shall receive the Royal Assent before the expiration of the time limit mentioned in subsection (1), or before a Referendum requested as aforesaid has taken place.
3. Where a Referendum on a Bill has been requested the Folketing may within a period of five week-days from the final passing of the Bill resolve that the Bill shall be withdrawn.
4. Where the Folketing has made no resolution in accordance with subsection (3), notice to the effect that the Bill will be put to a Referendum shall without delay be given to the Prime Minister, who shall then cause the Bill to be published together with a statement that a Referendum will be held. The Referendum shall be held in accordance with the decision of the Prime Minister not less than twelve and not more than eighteen week-days after the publication of the Bill.
5. At the Referendum votes shall be cast for or against the Bill. For the Bill to be rejected a majority of the electors taking part in the voting, however, not less than thirty per centum of all persons entitled to vote, shall have voted against the Bill.
6. Finance Bills, Supplementary Appropriation Bills, Provisional Appropriation Bills, Government Loan Bills, Civil Servants (Amendment) Bills, Salaries and Pensions Bills, Naturalization Bills, Expropriation Bills, Taxation (Direct and Indirect) Bills, as well as Bills introduced for the purpose of discharging existing treaty obligations shall not be subject to a decision by Referendum. This provision shall also apply to the Bills referred to in sections 8, 9, 10, and 11, and to such resolutions as are provided for in section 19, if existing in the form of a law, unless it has been provided by a special Act that such resolutions shall be put to a Referendum. Amendments of the Constitution Act shall be governed by the rules laid down in section 88.
7. In an emergency a Bill that may be subjected to a Referendum may receive the Royal Assent immediately after it has been passed, provided that the Bill contains a provision to that effect. Where under the rules of subsection (1) one-third of the Members of the Folketing request a Referendum on the Bill or on the Act to which the Royal Assent has been given, such Referendum shall be held in accordance with the above rules. Where the Act is rejected by the Referendum, an announcement to that effect shall be made by the Prime Minister without undue delay and not later than fourteen days after the Referendum was held. From the date of such announcement the Act shall become ineffective.
8. Rules for Referenda, including the extent to which Referenda shall be held on the Faeroe Islands and in Greenland, shall be laid down by Statute.
Section 19.
1. The King shall act on behalf of the Realm in international affairs. Provided that without the consent of the Folketing the King shall not undertake any act whereby the territory of the Realm will be increased or decreased, nor shall he enter into any obligation which for fulfilment requires the concurrence of the Folketing, or which otherwise is of major importance; nor shall the King, except with the consent of the Folketing, terminate any international treaty entered into with the consent of the Folketing.
2. Except for purposes of defence against an armed attack upon the Realm or Danish forces the King shall not use military force against any foreign state without the consent of the Folketing. Any measure which the King may take in pursuance of this provision shall immediately be submitted to the Folketing. If the Folketing is not in session it shall be convoked immediately.
3. The Folketing shall appoint from among its Members a Foreign Affairs Committee, which the Government shall consult prior to the making of any decision of major importance to foreign policy. Rules applying to the Foreign Affairs Committee shall be laid down by Statute.
The Danish Parliament, FACTS AND FIGURES: REFERENDA, 2012, accessed 24 September 2019
Certain international treaties (Section 42, Subsection 6 of the CA)
Section 42, Subsection 6 of the CA states that Bills ratifying international treaties can be put to a referendum if the Danish Parliament decides to try the ratification in a referendum by introducing a separate Bill.
This provision led to the referendum of 18 May 1993 on the Edinburgh Agreement. There was general agreement that there should be a referendum on the Edinburgh Agreement under any circumstances. And with prospect of more than 150 Members of the Danish Parliament voting for the Agreement, the possibility of holding a referendum would be excluded in accordance with Section 20 of the CA. The Edinburgh Agreement being an international treaty, it was therefore decided to ensure a referendum by having recourse to the provision which can be found in Section 42, Subsection 6 of the CA.