1Each Canton shall adopt a democratic constitution. This requires the approval of the People and must be capable of being revised if the majority of those eligible to vote so request.
2Each cantonal constitution shall require the guarantee of the Confederation. The Confederation shall guarantee a constitution provided it is not contrary to federal law.
Art. 51 BV governs the requirements for cantonal constitutions and their supervision by the Confederation. Every canton must adopt a democratic constitution (fundamental order of the canton) that must fulfil two central conditions: the people must be able to approve it, and it must be amendable when the majority so demands.
Democratic constitution means according to the Federal Council at least an elected parliament and separation of powers. Legal scholarship additionally requires regular elections, equal voting rights for all, and protection of minorities. It is disputed whether cantons may have a bicameral parliament - most legal scholars say no, but individual experts such as Belser and Massüger find it permissible for special reasons (such as protection of linguistic minorities).
The Confederation examines every cantonal constitution before it can take effect (federal guarantee). The Federal Assembly approves it only if it complies with all federal law - not only the Federal Constitution, but also all federal acts. Example: The Canton of Zurich wanted to introduce naturalisation by ballot in 2003. The Federal Supreme Court prohibited this because rejected applicants have a right to justification.
Legal consequences: No cantonal constitution can enter into force without the federal guarantee. Even after approval, the Federal Supreme Court continues to supervise: if federal law changes, the cantons must adapt their constitutions. Thus several cantons had to reform their electoral systems because new Federal Supreme Court decisions established stricter equality rules.
The provision secures the balance between cantonal self-determination and national legal unity in the federal state.
N. 1 The current provision of Art. 51 BV traces back to Art. 6 of the Federal Constitution of 1874, which in turn combined Art. 6 and 85 no. 7 of the Federal Constitution of 1848. The Federal Council Message on the Total Revision of the Federal Constitution of 20 November 1996 (BBl 1997 I 1) stated that the guarantee of cantonal constitutions represents a central element of the Swiss federal state. The provision secures cantonal constitutional autonomy on the one hand, while ensuring compliance with federal law on the other.
N. 2 During the 1999 total revision, a conscious decision was made not to specify the concept of "democratic constitution". The constitutional legislator did not want to impede the dynamic development of understanding of democracy through a rigid definition. The formulation "if they do not contradict federal law" replaced the earlier phrase "provided they contain nothing contrary to the provisions of the Federal Constitution" to clarify that the entire federal legal order serves as the standard (BBl 1997 I 252).
N. 3 Art. 51 BV stands in the second title on Confederation, Cantons and Communes. The provision must be read in conjunction with the principles of federalism: → Art. 3 BV (cantons as sovereign within the framework of the Federal Constitution), → Art. 47 BV (preservation of cantonal independence), → Art. 49 BV (precedence of federal law) and → Art. 52 BV (constitutional order).
N. 4 The guarantee under Art. 51 para. 2 BV is concretised by → Art. 172 para. 2 BV, which empowers the Federal Assembly to grant the guarantee. The procedure is governed by → Art. 189 para. 1 lit. e BV for Federal Supreme Court review. The provision is closely related to political rights (→ Art. 34 BV) and equality before the law (→ Art. 8 BV).
N. 5Cantonal constitution: The concept encompasses the formal constitution as the basic order of the canton. Belser/Massüger (BSK BV, Art. 51 N. 14) define it as a collection of legally supreme norms that organise the political system, guarantee fundamental rights and establish state functions. The cantonal constitution must be formally distinguished from other cantonal enactments.
N. 6Democratic constitution: The requirement of a democratic constitution requires, according to the Federal Council (cited in Belser/Massüger, BSK BV, Art. 51 N. 20), at least an elected parliament and observance of the principle of separation of powers. The prevailing doctrine (Belser/Massüger, BSK BV, Art. 51 N. 19) concretises this through four elements: periodic elections, universal and equal suffrage, majority principle and guaranteed opposition.
N. 7Consent of the people: The mandatory constitutional referendum forms the core of democratic legitimacy. BGE 121 I 138 E. 5 also recognised the Landsgemeinde as a permissible form despite systemic weaknesses. Consent must be given in a free and fair procedure.
N. 8Possibility of revision: The constitution must be revisable if the majority of those entitled to vote so demands. This encompasses both partial and total revisions. Blocking periods are, according to Kölz (Die Zulässigkeit von Sperrfristen für kantonale Volksinitiativen, ZBl 2001, 169), only permissible if they are proportionate.
N. 9Contradiction with federal law: The cantonal constitution may not contradict not only the Federal Constitution, but the entire federal law. This includes federal acts, ordinances and international treaties (→ Art. 190 BV). BGE 130 I 1 E. 2 confirmed this comprehensive standard of review.
N. 10Guarantee: The guarantee by the Federal Assembly has constitutive effect. Without guarantee, a cantonal constitution cannot come into force. The guarantee is granted by federal decree and may be subject to conditions (Hotz, Probleme bei der eidgenössischen Gewährleistung kantonaler Verfassungen, ZBl 1982, 193).
N. 11Federal Supreme Court review: The Federal Supreme Court may review guaranteed cantonal constitutional provisions in cases of application if federal law has developed since the guarantee was granted. BGE 140 I 394 E. 9 established this dynamic approach for electoral equality. However, the review only occurs in concrete cases of application, not abstractly.
N. 12Hierarchy of norms: The cantonal constitution enjoys intra-cantonal precedence over acts and ordinances. BGE 143 I 272 E. 2.3 emphasised: «In the normative structure of the canton, the constitution then enjoys normative precedence.» This precedence must also be observed in cantonal legal application.
N. 13Bicameral parliaments: The prevailing doctrine (cited in Belser/Massüger, BSK BV, Art. 51 N. 33) considers cantonal bicameral parliaments inadmissible as they contradict the principle of equality. Belser/Massüger (BSK BV, Art. 51 N. 33) argue conversely that a bicameral system could indeed be democratic with factual reasons such as protection of linguistic minorities. Practice knows no cantonal bicameral parliaments.
N. 14Qualified majorities: Another point of dispute concerns qualified majority requirements. The prevailing doctrine (Belser/Massüger, BSK BV, Art. 51 N. 39) rejects these as undemocratic. Belser/Massüger (BSK BV, Art. 51 N. 39) argue more differentially: qualified majorities should be permissible with factual justification, for instance to protect national minorities. The Federal Supreme Court has not yet decided this question.
N. 15Majoritarian electoral systems: The admissibility of pure majoritarian electoral procedures for cantonal parliaments is disputed. Hangartner (Die Wahl kantonaler Parlamente nach dem Majorzsystem, ZBl 2005, 217) considers them contrary to federal law. BGE 145 I 259 E. 5 ultimately left the question open, but emphasised the strict requirements for constituency division in majoritarian systems.
N. 16Constitutional revisions: For total revisions, contact should be sought early with the Federal Office of Justice. The informal preliminary examination can avoid later guarantee problems. Partial revisions also require guarantee, but the procedure is simplified (Bundi Caldelari/Rathgeb, ZGRG 2004, 92).
N. 17Electoral reforms: Reforms of the cantonal electoral system must observe the developing Federal Supreme Court practice on electoral equality. BGE 143 I 92 E. 3 requires cross-constituency equality of success value in mixed systems. Pure majoritarian systems are subject to heightened requirements.
N. 18Municipal organisation: The guarantee also covers provisions on municipal organisation. BGE 131 I 91 E. 3 accepted forced mergers but requires procedures under the rule of law. Municipal autonomy (→ Art. 50 BV) must be observed as a limitation.
N. 19Dynamic guarantee: The guarantee once granted does not apply absolutely. In case of substantial changes to federal law or constitutional interpretation, adjustment may be necessary. BGE 139 I 195 E. 3 shows that constitutional provisions contrary to federal law may not be perpetuated.
N. 20Procedural questions: Against the refusal of guarantee, recourse to the Federal Supreme Court is available (→ Art. 82 lit. b FSCA). The appeal is governed by → Art. 189 para. 1 lit. e BV. In the application of guaranteed norms, the Federal Supreme Court examines compatibility with higher-ranking law (Cereghetti, Die Überprüfung der Kantonsverfassungen, 1956, 45ff.).
BGE 143 I 272 E. 2.2-2.5 of 3 April 2017
The Federal Supreme Court fundamentally clarified the precedence of cantonal constitutions and the limits of federal judicial review. The decision concerned the forced merger of school municipalities in Zurich.
«Regarding the hierarchy of norms, it can only be derived from the Federal Constitution that all federal law (Art. 49 para. 1 Cst.) and intercantonal law (Art. 48 para. 5 Cst.) supersedes contradicting cantonal law. The intracantonal norm hierarchy remains unmentioned. According to Art. 51 para. 1 Cst., however, each canton adopts a democratic constitution. In the normative structure of the canton, the constitution then takes normative precedence.»
BGE 140 I 394 E. 9 of 26 September 2014
The Federal Supreme Court specified its authority to review cantonal constitutional provisions in concrete cases using the example of the electoral procedure in Appenzell Ausserrhoden.
«The principle of electoral equality flowing from Art. 34 Cst. has been further developed since the guarantee of the Constitution of the Canton of Appenzell A.Rh. by the Federal Assembly in 1996. This development must be taken into account, which is why the Federal Supreme Court examines, following an appeal concerning the 2011 election of the Cantonal Council of Appenzell A.Rh., whether the electoral procedure regulated in its basic features in the cantonal constitution is compatible with electoral equality.»
BGE 145 I 259 E. 5 of 29 July 2019
The decision concerns the compatibility of the majoritarian electoral system in Graubünden with the requirements for a democratic constitution under Art. 51 para. 1 Cst.
«The prerequisites for the review of provisions of a cantonal constitution by the Federal Supreme Court. The size of the Swiss resident population as a permissible criterion for the distribution of seats among electoral districts. Question of the admissibility of seat guarantees for electoral districts with insufficient population.»
BGE 121 I 138 E. 5 of 5 June 1995
The Federal Supreme Court recognised the Landsgemeinde as a constitutionally compliant democratic system despite systemic inadequacies.
«The institution of Landsgemeinden corresponds to a special traditional form of direct democratic participation by voters. [...] The ordering of a Landsgemeinde vote does not violate freedom of vote despite systemic inadequacies.»
BGE 129 I 232 E. 2-5 of 9 July 2003
The Federal Supreme Court examined an initiative to introduce ballot votes on naturalisation applications and declared it invalid due to violation of fundamental federal rights.
«Negative naturalisation decisions are subject to the duty to give reasons according to Art. 29 para. 2 Cst. (right to be heard) in conjunction with Art. 8 para. 2 Cst. (prohibition of discrimination). In ballot votes, reasoning that meets constitutional requirements is not possible.»
BGE 130 I 1 E. 2 of 19 November 2003
The Federal Supreme Court confirmed the precedence of federal law in a conflict between cantonal constitution and federal legislation in the asylum area.
«Art. 51 para. 2 Cst. provides that cantonal constitutions require the guarantee of the Confederation. The Confederation guarantees them if they do not contradict federal law.»
BGE 131 I 91 E. 3 of 28 September 2004
The decision on municipal merger in Valais clarified the limits of cantonal autonomy in forced mergers.
The court found that forced mergers of municipalities are fundamentally compatible with municipal autonomy if cantonal law provides for corresponding procedures.
BGE 136 I 352 E. 4 of 7 July 2010
The Federal Supreme Court examined the proportional electoral system in Nidwalden and specified the requirements for democratic electoral procedures.
The court held that cantonal electoral procedures must comply with federal constitutional minimum standards, but that cantons have considerable scope for design.
BGE 147 I 478 E. 2 of 25 June 2021
The Federal Supreme Court dealt with the norm hierarchy in the Canton of Schwyz during the Covid-19 pandemic and reaffirmed the importance of the guarantee.
The decision emphasised that even in exceptional situations, guaranteed cantonal constitutional provisions must be respected.
BGE 139 I 195 E. 3 of 10 July 2013
The decision on a proportional electoral procedure in the Canton of Zug assessed as contrary to the Federal Constitution clarified the limits of a guarantee once granted.
«The disputed voting proposal is inadmissible because it is aimed at enabling the introduction of an electoral procedure that violates electoral law.»
The Federal Supreme Court clarified that the guarantee of a cantonal constitution does not apply for all time, but must be adapted in light of subsequent developments in federal law.