The Sonderbund was in violation of the Federal Treaty of 1815, §6, which expressly forbade such separate alliances, and the Radical majority in the Tagsatzung decided to dissolve the Sonderbund on 21 October 1847. The confederate army was raised against the members of the Sonderbund. The army was composed of soldiers of all the other states except Neuchâtel and Appenzell Innerrhoden which had stayed neutral.
The war lasted for less than a month, causing fewer than 100 casualties. Apart from small riots, this was the last armed conflict on Swiss territory.
At the end of the Sonderbund War, the Diet began to debate a new federal constitution drawn up by Johann Conrad Kern (1808-1888) of Thurgau and Henri Druey (1790-1855) of Vaud. In the summer of 1848 this constitution was accepted by fifteen and a half cantons with Uri, Schwyz, Unterwalden, Valais, Ticino and Appenzell Innerrhoden opposing. The new constitution was declared on September 12, 1848.
A federal central government was set up to which the cantons gave up certain parts of their sovereign rights, retaining the rest. The Federal Assembly was made up of two houses- Council of States (Ständerat), composed of two deputies from each canton (44 members at the time) and the National Council (Nationalrat) made up of deputies elected three years, in the proportion of one for every 20,000 citizens or fraction over 10,000 from each canton. The Federal Council or executive (Bundesrat) consisted of seven members elected by the Federal Assembly. In the 1848 Constitution, the entire Federal Council was granted the "supreme executive and directorial authority of the Confederation". Each member of the Federal Council heads one of seven executive departments. The chairman of the Council also holds the title of President of the Swiss Confederation for a one year term, with the position rotating among the members of the Federal Council.
The judiciary (Bundesgericht) was made up of eleven members elected for three years by the Federal Assembly. The Bundesgericht was chiefly confined to civil cases in which the Confederation was a party, but also took in also great political crimes. All constitutional questions are however reserved for the Federal Assembly.
A Federal university and a polytechnic school were to be founded. All military capitulations were forbidden in the future. Every canton must treat Swiss citizens who belong to one of the Christian confessions like their own citizens. All Christians were guaranteed the exercise of their religion but the Jesuits and similar religious orders were not to be received in any canton. German, French and Italian were recognized as national languages.
The constitution as a whole marked a great step forward; though very many rights were still reserved to the cantons, yet there was a fully organized central government. Almost the first act of the Federal Assembly was to exercise the power given them of determining the home of the Federal authorities, and on the 28th of November 1848 Berne was chosen. The first Federal Council sat on 16 November 1848, composed entirely of members of the Free Democratic Party.
Some of the first acts of the new Federal Assembly were to unify and standardize daily life in the country. In 1849 a uniform postal service was established. In 1850 a single currency replaced the intricate cantonal currencies, while all customs between cantons were abolished. In 1851 the telegraph was organized, while all weights and measures were unified. In 1868 the metric system was allowed and in 1875 declared obligatory and universal. In 1854 roads and canals taken in hand were taken under federal control. The Federal Polytechnic wasn't opened until 1855 in Zurich, though the Federal university authorized by the new constitution has not yet been set up.
In 1866 the rights granted only to Christians (free movement and freedom of religion) under the 1848 Constitution, were extended to all Swiss regardless of religion.
The Constitution of 1874 further strengthened the federal power. The revised Constitution included three major points. First, a system of free elementary education was set up, under the superintendence of the Confederation, but managed by the cantons. Second, a man settling in another canton was, after three months (instead of two years in the 1848 Constitution), given all cantonal and communal rights (formerly only cantonal rights were granted). Finally, the referendum was introduced in its "facultative" form; i.e., all federal laws must be submitted to popular vote on the demand of 30,000 Swiss citizens or of eight cantons. The Initiative (i.e., the right of compelling the legislature to consider a certain subject or bill) was not introduced into the Federal Constitution until 1891 (when it was given to 50,000 Swiss citizens) and then only as to a partial (not a total) revision of that constitution.