#1. Legislative History
N. 1 The current provision of Art. 136 Cst. dates back to the total revision of the Federal Constitution of 1999 and continues the tradition of political rights from Art. 43 old Cst. The reduction of the voting age from 20 to 18 years already took place in 1991 through popular vote (BBl 1991 I 1201). The formulation of the grounds for disqualification was modernised, whereby the reference to «mental illness or mental deficiency» was maintained despite contemporary criticism (BBl 1997 I 1, 390). The constituent power deliberately decided against a gender-neutral formulation and maintained the explicit mention of «Swiss women and men» in order to constitutionally anchor the political equality of women that was only achieved in 1971.
#2. Systematic Classification
N. 2 Art. 136 Cst. forms the foundation of political rights at the federal level and systematically stands at the beginning of the chapter on political rights (Art. 136–142 Cst.). The provision concretises the political rights guaranteed in Art. 34 Cst. as a fundamental right for the federal level. It is closely related to:
N. 3 The norm is conceived as a conclusive regulation of the voting requirements at the federal level. The legislature may neither add new requirements nor modify the stated requirements.
#3. Elements of the Offence / Content of the Norm
N. 4 Nationality: Voting rights require Swiss nationality. Dual citizens are entitled to vote provided they meet the other requirements. The voting right for Swiss abroad is guaranteed by Art. 40 Cst.
N. 5 Majority: The 18th year of age must be completed. The day of the 18th birthday is decisive, not the calendar year. The discussion about a further reduction of the voting age or a children's voting right through legal representatives was rejected by the constituent power. Part of the literature rejects the children's voting right because it would in practice give the legal representative a second vote and would conflict not only with equality before the law but, even more so, with the role of the electorate as an organ of the state.
N. 6 Deprivation of civil rights: The exclusion due to «mental illness or mental deficiency» has been obsolete since the revision of adult protection law in 2013. Art. 136 Cst. must be interpreted in light of Art. 14 CC: Only comprehensive deputyship leads to the loss of political rights. The outdated terminology of the Constitution is regrettable, but does not change the restrictive interpretation.
N. 7 Equality of political rights: Paragraph 1 sentence 2 guarantees the equality of political rights. This includes equality of counting value (each vote counts equally), but not equality of success value (each vote has equal influence on the result). Some commentators criticise that sentence 2 of Art. 136 para. 1 stands in isolation and would better have been left out, since equality already follows from Art. 8 Cst.
#4. Legal Consequences
N. 8 Active voting right: Those entitled to vote may participate in National Council elections and federal votes (para. 2). The right to vote includes the right to elect, but not to be elected (passive eligibility, → Art. 143 Cst.).
N. 9 Right of initiative and referendum: Those entitled to vote may sign and launch popular initiatives (→ Art. 138, 139 Cst.) and referendums (→ Art. 140, 141 Cst.). The collection of signatures on public ground is protected as an exercise of political rights (BGE 135 I 302).
N. 10 Obligation to participate: The «duties» mentioned in para. 1 refer to the compulsory voting that exists in individual cantons. At the federal level there is no obligation to participate.
#5. Disputes
N. 11 Voting age: The demand for a reduction of the voting age to 16 years is controversially discussed. Supporters like Caroni (Herausforderung Demokratie, ZSR 2013 II 5, 45 ff.) argue with the political maturity of young people and demographic development. Critics like Hangartner/Kley (Die demokratischen Rechte in Bund und Kantonen, 2nd ed. 2022, N. 862) refer to the necessary correspondence between voting rights and civil law majority.
N. 12 Swiss abroad: The equal treatment of Swiss abroad regarding political rights is disputed. While Aubert/Mahon (Petit commentaire, 2003, Art. 136 N. 4) support complete equal treatment, Biaggini (Komm. BV, 2nd ed. 2017, Art. 136 N. 7) argues for restrictions on cantonal and communal matters due to the lack of connection.
#6. Practice Notes
N. 13 Electoral register: The cantons maintain the electoral registers and are responsible for their accuracy (→ Art. 39 para. 2 Cst.). Objections to entries or non-entries are to be directed to the cantonal authorities.
N. 14 Double counting: In case of dual citizenship within Switzerland, it must be ensured that voting takes place only in one municipality. The electronic networking of electoral registers is gaining importance.
N. 15 Recusal rules: Despite the equality of political rights, cantonal recusal rules for parliamentarians in cases of personal conflicts of interest may be permissible, but may not generally exclude entire groups of persons (BGE 125 I 289, BGE 123 I 97).