Until 1918, Viennese politics were shaped by the Christian Social Party. Vienna is today considered the centre of the Social Democratic Party of Austria. For most of the time since the First World War, the city has been governed by the Social Democratic Party with absolute majorities in the city parliament. Only between 1934 and 1945, when the Social Democratic Party was illegal, mayors were appointed by the austro-fascist and later by the Nazi authorities. The current mayor of Vienna is Michael Häupl. The Social Democrats currently hold 55% of the seats with a 49% share of the vote.

Ever since Vienna obtained federal state (Bundesland) status of its own in 1921, the mayor has also had the role of the state governor (Landeshauptmann). The Rathaus accommodates the offices of the mayor and the state government (Landesregierung). The city is administered by a multitude of departments (Magistratsabteilungen). The parliament of Austria is located in Vienna.

Austria became a federal, parliamentarian, democratic republic through the Federal Constitution of 1920. It was reintroduced in 1945 to the nine states of the Federal Republic. The head of state is the Federal President (Bundespräsident), who is directly elected by popular vote. The chairman of the Federal Government is the Federal Chancellor, who is appointed by the president. The government can be removed from office by either a presidential decree or by vote of no confidence in the lower chamber of parliament, the Nationalrat.

Source

• http://en.wikipedia.org/wiki/Vienna#Politics