Prior to 1798, the Swiss Confederacy was a confederation of independent states, not a federal state, and as such was based on treaties rather than a constitution. The Helvetic Republic of 1798–1803 had a constitution largely drawn up by Peter Ochs, in 1803 replaced by the Act of Mediation, which was in turn replaced by the Federal Treaty of 1815, which restored the Confederacy, while the individual cantons drew up cantonal constitutions, in most respects based on the Ancien Régime
of the 18th century, but with notable liberal innovations in the constitutions of the new cantons of St. Gallen, Aargau, Thurgau, Ticino, Vaud and Geneva. The new cantonal constitutions in many cases served as precedents for the later federal constitution.
Following the French July Revolution in 1830, a number of large assemblies were held calling for new cantonal constitutions.
The modifications to the cantonal constitutions made during this period of "Regeneration" remains the basis of the current-day cantonal constitutions. Vaud introduced the legislative popular initiative in 1846. Berne introduced the legislative optional referendum in the same year.
The political crisis of the Regeneration period culminated in the Sonderbund War of November 1847.
As a result of the Sonderbund War, Switzerland was transformed into a federal state, with a constitution promulgated on 12 September 1848. This constitution provided for the cantons' sovereignty, as long as this did not impinge on the Federal Constitution.
The creation of a bicameral assembly was consciously inspired by the United States Constitution,
the National Council and Council of States corresponding to the House of Representatives and Senate, respectively.
The Constitution of 1848 was partly revised in 1866, and wholly revised in 1874. This latter constitutional change introduced the referendum at the federal level.
In a partial revision of 1891, the "right of initiative" was introduced, under which a certain number of voters could make a request to amend a constitutional article, or even to introduce a new article into the constitution. This mechanism is called federal popular initiative. Thus, partial revisions of the constitution could – from this time onward – be made at any time.
Twelve such changes were made in the period of 1893 to 1994 (with no changes during the thirty-year period of 1950–1980):
The Federal Constitution was wholly revised for the second time in the 1990s, and the new version was approved by popular and cantonal vote on 18 April 1999. It came into force on 1 January 2000.
The 1999 Constitution of Switzerland consists of a Preamble and 6 Parts, which together make up 196 Articles.
It provides an explicit provision for nine fundamental rights, which up until then had only been discussed and debated in the Federal Court. It also provides for greater details in tax laws. The Constitution of 1999 has been changed by popular initiative ten times in the period of 2002 to 2014, as follows:
- 3 March 2002: Accession to the United Nations
- 8 February 2004: Indefinite confinement of dangerous sexual offenders
- 27 November 2005: Restrictions on the use of genetically modified organisms in agriculture
- 30 November 2008: Abolition of the statute of limitations for child sexual abuse
- 29 November 2009: Prohibition of minarets
- 28 November 2010: extradition of convicted foreign citizens
- 11 March 2012: Limitation on building permits for holiday homes
- 3 March 2013: Provisions for the right of shareholders in Swiss public companies to determine executive pay
- 9 February 2014: Principle of immigration quotas
- 8 May 2014: Prohibition of convicted pedophiles from working with minors