The upper house, or Senate, elects members every two years for six-year terms (81 total); the lower house, or Chamber of Deputies, has 200 members who are elected for four-year terms. The political parties often join together in coalitions to form a majority or other bloc of votes in the government. Five parties have 10 or more representatives in the Chamber of Deputies; one deputy is an independent (Czechcentrum.cz). More parties hold seats in the Senate, but only two hold more than 10 seats, the Civic Democratic Party (ODS) and the Coalition of Four (tykoalice), a coalition of four smaller political parties.
The country's oldest political party is the Czech Social Democratic Party (CSSD), formed in 1878 under the old Austro-Hungarian Empire. According to the official Czech government website, the CSSD helped in the formation of Czechoslovakia after WWI and merged with the Communist Party in 1948. It favors a "social market" economy but has also led the drive to privatize former state-owned industries, including the country's large telecommunications system. It is considered left-of-center. The CSSD is most popular with working-class voters in industrial centers, trade union members and public service employees. It is similar to the Social Democratic Party in Germany and the British Labour Party and strongly in favor of the European Union, which the country joined in 2004.