Government
Type: Republic since June 2, 1946.
Constitution: January 1, 1948.
Branches: Executive--president (chief of state), Council of Ministers (cabinet), headed by the president of the council (prime minister). Legislative--bicameral parliament: 630-member Chamber of Deputies, 315-member Senate (plus a varying number of "life" Senators). Judicial--independent constitutional court and lower magistracy.
Subdivisions: 94 provinces, 20 regions.
Political parties: Forza Italia, Democratic Party of the Left, National Alliance, Northern League, United Christian Democrats, Democrats, Italian People's Party, Christian Democratic Center, Socialist, Communist Renewal, Social Democratic, Republican, Liberal, Greens, Italian Renewal.
Suffrage: Vote for House; universal over 18; vote for Senate; universal over 18.

Government of Italy
Italy has been a democratic republic since June 2, 1946, when the monarchy was abolished by popular referendum. The constitution was promulgated on January 1, 1948.

The Italian state is centralized. The prefect of each of the provinces is appointed by and answerable to the central government. In addition to the provinces, the constitution provides for 20 regions with limited governing powers. Five regions--Sardinia, Sicily, Trentino-Alto Adige, Valle d'Aosta, and Friuli-Venezia Giulia--function with special autonomy statutes. The other 15 regions were established in 1970 and vote for regional "councils." The establishment of regional governments throughout Italy has brought some decentralization to the national governmental machinery, and recent governments have devolved further powers to the regions. However, many regional governments, particularly in the north of Italy, are seeking additional powers.

The 1948 constitution established a bicameral parliament (Chamber of Deputies and Senate), a separate judiciary, and an executive branch composed of a Council of Ministers (cabinet), headed by the president of the council (prime minister). The president of the republic is elected for 7 years by the parliament sitting jointly with a small number of regional delegates. The president nominates the prime minister, who chooses the other ministers. The Council of Ministers--in practice composed mostly of members of parliament--must retain the confidence of both houses.

The houses of parliament are popularly and directly elected by a mixed majoritarian and proportional representation system. Under 1993 legislation, Italy has single-member districts for 75% of the seats in parliament; the remaining 25% of seats are allotted on a proportional basis. The Chamber of Deputies has 630 members. In addition to 315 elected members, the Senate includes former presidents and several other persons appointed for life according to special constitutional provisions. Both houses are elected for a maximum of 5 years, but either may be dissolved before the expiration of its normal term. Legislative bills may originate in either house and must be passed by a majority in both.

The Italian judicial system is based on Roman law modified by the Napoleonic code and subsequent statutes. There is only partial judicial review of legislation in the American sense. A constitutional court, which passes on the constitutionality of laws, is a post-World War II innovation. Its powers, volume, and frequency of decisions are not as extensive as those of the U.S. Supreme Court.
source: http://www.state.gov