1The following must be put to the vote of the People and the Cantons:
amendments to the Federal Constitution;
accession to organisations for collective security or to supranational communities;
emergency federal acts that are not based on a provision of the Constitution and whose term of validity exceeds one year; such federal acts must be put to the vote within one year of being passed by the Federal Assembly.
2The following are submitted to a vote of the People:
popular initiatives for a total revision of the Federal Constitution;
abis.
popular initiatives for a partial revision of the Federal Constitution in the form of a general proposal that have been rejected by the Federal Assembly;
the question of whether a total revision of the Federal Constitution should be carried out, in the event that there is disagreement between the two Councils.
Overview
Art. 140 FC regulates when the Swiss people must vote on important political decisions. The provision distinguishes between two procedures: the mandatory referendum (paragraph 1) and the mandatory popular vote (paragraph 2).
In the mandatory referendum, both the people and the cantons (states) must give their consent. This applies to three cases: All constitutional amendments are automatically subject to this rule — even small textual changes trigger a vote (Epiney/Diezig, BSK BV, Art. 140 N. 10). Second, accession to international security organisations or supranational communities must be put before the people. Supranational communities are, according to the Federal Council's definition, organisations with independent bodies that can issue directly binding decisions by majority decision (Federal Council, cited in Epiney/Diezig, BSK BV, Art. 140 N. 18). The EU is the classic example of this. For the European Economic Area (EEA), it is disputed whether it is supranational (Epiney/Diezig, BSK BV, Art. 140 N. 19). Third, urgent federal acts without a constitutional basis are put before the people if they remain in force for longer than one year.
In the mandatory popular vote, only the people decide, without the cantons having to give their consent. This concerns popular initiatives for a total revision of the constitution and rejected initiatives in the form of a general suggestion. If the National Council and Council of States cannot agree on whether a total revision is necessary, the people also decide.
Example: If Switzerland wants to join the EU, both people and states must consent, as the EU is a supranational community. If someone wants to launch a popular initiative for a complete constitutional renewal, a popular majority is sufficient.
The vote takes place automatically — the authorities have no choice (Art. 140 is exhaustive, Epiney/Diezig, BSK BV, Art. 140 N. 10). Parliamentary resolutions on conducting such referendums cannot be challenged before the Federal Court (Judgment 1C_529/2022 E. 3).
N. 1 Art. 140 FC continues the tradition of the mandatory referendum that has been enshrined since the Federal Constitution of 1848. The provision was consolidated from Arts. 89, 89bis, 120, 121 and 123 old FC during the total revision of 1999 and systematically reorganized (BBl 1997 I 418 ff.).
N. 2 The most important substantive innovation concerns Art. 140 para. 1 lit. b FC: Accession to supranational communities was explicitly made subject to the mandatory referendum for the first time. This addition was made in response to the EEA referendum of 1992 and was intended to strengthen democratic legitimation for far-reaching integration steps (BBl 1997 I 420).
N. 3 The deletion of Art. 140 para. 2 lit. abis FC (counter-proposals by the Federal Assembly to popular initiatives for total revision) took place in 2003 as part of the Political Rights Reform, since this provision had never been applied in practice (BBl 2001 4803).
N. 4 Art. 140 FC, together with Art. 138 (popular initiative for total revision), Art. 139 (popular initiative for partial revision) and Art. 141 (optional referendum), forms the core system of direct democratic participation rights at the federal level. The provision conclusively regulates in which cases a mandatory referendum must be conducted (Epiney/Diezig, BSK BV, Art. 140 N. 10).
N. 5 The mandatory referendum under Art. 140 para. 1 FC differs from the optional referendum (Art. 141 FC) by three characteristics: It takes place automatically without signature collection, requires the approval of the people and cantons (double majority) and concerns particularly important constitutional matters.
N. 6 The systematic division into para. 1 (people and cantons) and para. 2 (people only) follows the logic that constitutional amendments and fundamental treaty matters require federative consent, while popular initiatives as an instrument of popular sovereignty are subject only to the majority of the people.
#a) Paragraph 1: Mandatory Referendum of People and Cantons
N. 7Constitutional amendments (lit. a): Every formal amendment to the Federal Constitution is subject to the mandatory referendum, regardless of its substantive significance. This also includes purely editorial adjustments or the repeal of obsolete provisions (→ Art. 195 FC).
N. 8Organizations for collective security (lit. b): According to the Federal Council definition, these are universal or regional organizations that set themselves the goal of offering organized resistance to an aggressor state that breaks the peace (Federal Council, cited in Epiney/Diezig, BSK BV, Art. 140 N. 17). A classic example would be the United Nations with its Chapter VII system.
N. 9Supranational communities (lit. b): The Federal Council defines these as organizations with independent organs that can issue directly binding decisions for individuals through majority decisions and have relatively comprehensive substantive powers (Federal Council, cited in Epiney/Diezig, BSK BV, Art. 140 N. 18). The EU unquestionably meets these criteria.
N. 10 The classification of the EEA is disputed: Epiney/Diezig (BSK BV, Art. 140 N. 19) as well as Hangartner/Kley affirm supranationality because of the dynamic legal development and the powers of the EFTA Surveillance Authority. Häfelin/Haller/Keller, Tschannen and Biaggini, however, deny it, since EEA law is not directly applicable and the adoption of new legal acts requires the consent of the contracting parties.
N. 11Urgent federal acts without constitutional basis (lit. c): This rare constellation concerns only federal acts that cumulatively: (1) have been declared urgent by the Federal Assembly (→ Art. 165 FC), (2) have no constitutional basis and (3) whose period of validity exceeds one year. They must be put to the vote within one year of adoption.
N. 12Popular initiatives for total revision (lit. a): No such initiative has been submitted since the Federal Constitution of 1999. The procedure is regulated in Art. 138 FC. Unlike partial revision, there is no counter-proposal by the Federal Assembly (↔ Art. 139 FC).
N. 13Rejected popular initiatives in the form of a general suggestion (lit. b): This form of popular initiative (→ Art. 139 para. 2 FC) hardly occurs in practice. If the Federal Assembly rejects the general suggestion, it submits it to the people for voting. If adopted by the people, the Federal Assembly must draft a corresponding proposal.
N. 14Disagreement about total revision (lit. c): If the National Council and Council of States cannot agree on whether a total revision should be carried out, the people decide. This provision has never been applied.
N. 15 For matters under para. 1, the approval of the people and cantons is required (double majority). The popular majority is calculated according to the majority of valid votes cast nationwide, the cantonal majority according to the majority of cantons (→ Art. 142 FC).
N. 16 For matters under para. 2, the simple popular majority suffices. A cantonal majority is not required, which privileges popular initiative instruments over ordinary constitutional amendments.
N. 17 The conduct of the mandatory referendum is mandatory. There is no discretion and no possibility of waiver. The Federal Assembly must order the vote when the statutory requirements are met (→ Art. 13 para. 1 lit. d PubA).
N. 18 The voting deadline is not legally fixed. Practice shows that typically 3–12 months lie between parliamentary decision and popular vote. For urgent federal acts, the one-year deadline of Art. 140 para. 1 lit. c FC applies as an absolute upper limit.
N. 19Conclusive character: The prevailing doctrine (Epiney/Diezig, BSK BV, Art. 140 N. 10; Häfelin/Haller/Keller/Thurnherr, Bundesstaatsrecht, § 1383) holds that Art. 140 FC conclusively regulates the cases of mandatory referendum. A minority advocates for an extraordinary mandatory treaty referendum for particularly important international treaties that do not fall under lit. b (Schulte, Direkte Demokratie und Aussenpolitik, 287 ff.).
N. 20Supranationality of the EEA: The dispute over the legal qualification of the EEA divides the doctrine. Proponents of supranationality (Epiney/Diezig, BSK BV, Art. 140 N. 19; Hangartner/Kley, Demokratische Rechte, § 831) point to the dynamic legal development and the quasi-judicial powers of the EFTA Surveillance Authority. The opposing view (Häfelin/Haller/Keller, § 1932; Tschannen, Staatsrecht, § 15 N. 28; Biaggini, BV-Kommentar, Art. 140 N. 4) emphasizes that EEA law requires implementation and has no direct effect.
N. 21Concept of collective security: Villiger (FS Schindler, 805) advocates a broad interpretation that also covers regional security alliances with limited membership. The majority view (Thürer, SZIER 2005, 42; Ehrenzeller, FS Steinberger, 718) restricts the concept to universal or quasi-universal systems like the UN.
N. 22 When drafting constitutional provisions, it should be noted that even marginal textual changes trigger the mandatory referendum. Purely editorial adjustments should therefore be bundled with substantive revisions.
N. 23 For international treaties, it should be examined early whether the organization exhibits characteristics of supranationality. Decisive factors are: (1) independence of organs, (2) majority decisions, (3) direct applicability of decisions, (4) scope of transferred powers (Epiney, SJZ 1992, 285).
N. 24 The qualification of a federal act as urgent without constitutional basis under Art. 165 para. 2 FC automatically triggers the mandatory referendum if the period of validity exceeds one year. This constitutional consequence must be considered during parliamentary deliberation (Glaser, ZBl 2012, 525).
N. 25 Appeals against the incorrect application of Art. 140 FC are problematic since acts of the Federal Assembly are in principle not challengeable (→ Art. 189 para. 4 FC). The correct assignment to the mandatory or optional referendum must therefore be ensured primarily in the parliamentary procedure.
Judgment 1C_461/2025 of 2 October 2025 Federal Popular Vote on Federal Decree concerning Cantonal Property Taxes on Secondary Residences
The Federal Supreme Court confirmed the application of the mandatory referendum for a constitutional amendment under Art. 127 para. 2bis FC. It established that this constitutional amendment was subject to the mandatory referendum and had to be submitted to the People and Cantons for voting.
«This constitutional amendment was subject to the mandatory referendum and had to be submitted to the People and Cantons for voting (Art. 140 para. 1 lit. a FC and Section II para. 1 of said decree).»
Judgment 1C_348/2015 of 19 August 2015 (cons. 4) Popular Vote on RTVA Amendment
The Federal Supreme Court clarified the distinction between mandatory and optional referendum. The Court explained that constitutional amendments are subject to the mandatory referendum and are submitted to the People and Cantons for voting, while federal acts are subject to the optional referendum and are only submitted to the People for voting.
«Whereas amendments to the Federal Constitution are subject to the mandatory referendum and are submitted to the People and Cantons for voting (Art. 140 para. 1 lit. a FC), federal acts - such as the amendment of 26 September 2014 to the RTVA - are submitted to the People for voting in the framework of an optional referendum if 50,000 eligible voters or eight cantons so demand (Art. 141 para. 1 lit. a FC).»
#2. Accession to International Organisations (lit. b)
Case law on Art. 140 para. 1 lit. b FC is sparse, as accession to organisations for collective security or supranational communities rarely occurs in practice. The few available decisions mainly address procedural aspects in connection with international agreements that do not fall under this provision.
#3. Urgent Federal Acts without Constitutional Basis (lit. c)
Judgment 1C_529/2022 of 31 October 2022 Political Rights Complaint against Urgent Energy Act
The Federal Supreme Court dealt with a complaint against the declaration of urgency of a federal act. The complainants argued that the act should have been subject to the mandatory referendum under Art. 140 para. 1 lit. c FC. The Federal Supreme Court did not consider the complaint, as acts of the Federal Assembly are not subject to appeal.
«The Federal Assembly adopted the amendment to the Energy Act (Urgent Measures for Short-term Provision of Secure Electricity Supply in Winter) on 30 September 2022. The act was declared urgent (Art. 165 para. 1 FC) and made subject to the optional referendum (Art. 141 para. 1 lit. b FC). Against this, A.________ and 22 co-parties filed a political rights complaint and requested [...] alternatively that the declaration of urgency and the referendum clause be revoked and the Federal Council be obligated to conduct a mandatory referendum under Art. 140 lit. c FC for this amendment to the Energy Act.»
The judgment shows the practical difficulties in legal protection against the qualification of urgent federal acts, as such decisions of the Federal Assembly are in principle not subject to appeal (Art. 189 para. 4 FC).
#1. Popular Initiatives for Total Revision of the Constitution (lit. a)
No published Federal Supreme Court decisions are available on the practical application of Art. 140 para. 2 lit. a FC, as no popular initiative for total revision of the Federal Constitution has been submitted since 1999.
#2. Popular Initiatives for Partial Revision in the Form of General Proposal (lit. b)
BGE 139 II 303 (cons. 5) Referendum Deadline for International Treaties
Although this decision primarily concerned the optional referendum, it contains important principles for calculating voting deadlines that also apply to mandatory popular votes under Art. 140 para. 2 FC. The Federal Supreme Court established that the referendum deadline begins with publication in the Federal Gazette.
«The referendum deadline of 100 days begins with the publication of the enactment in the Federal Gazette. There is no binding rule that referendum deadlines always begin only eleven days after the decision of the federal chambers.»
#3. Disagreement between the Two Chambers on Total Revision (lit. c)
This provision has never been applied in practice, which is why no case law exists on it.
#1. Ground for Non-Entry on Complaints against Parliamentary Decisions
Judgment 1C_529/2022 of 31 October 2022 (cons. 3) Non-Appealability of Parliamentary Decisions
The Federal Supreme Court clarified that decisions of the Federal Assembly on conducting referendums are in principle not subject to appeal. This creates a gap in legal protection regarding control of the correct application of Art. 140 FC.
«According to Art. 189 para. 4 FC, acts of the Federal Assembly and the Federal Council cannot be appealed to the Federal Supreme Court, unless the law provides otherwise. This also applies to complaints for violation of political rights.»
Judgment 1C_348/2015 of 19 August 2015 (cons. 5) Recount for Close Voting Results
The Federal Supreme Court clarified the requirements for ordering a recount in federal votes. A general right to recount very close results exists only when there are concrete indications of irregularities.
«Art. 77 para. 1 lit. b FPRA must therefore now be interpreted such that a general and unconditional right to recount a very close or extremely close result of a federal vote exists only when additional external indications suggest that counting was not conducted correctly.»