Government
Type: Federative republic.
Independence: September 7, 1822.
Constitution: Promulgated October 5, 1988.
Branches: Executive--president (chief of state and head of government popularly elected to no more than two 4-year terms). Legislative--Senate (81 members popularly elected to 8-year terms), Chamber of Deputies (513 members popularly elected to 4-year terms). Judicial--Supreme Federal Tribunal (11 lifetime positions appointed by the president).
Political parties: Brazilian Democratic Movement Party (PMDB), Brazilian Social Democratic Party (PSDB), Liberal Front Party (PFL), Social Democratic Party (PSD), Democratic Workers Party (PDT), Workers Party (PT), Brazilian Labor Party (PTB), Liberal Party (PL), Brazilian Socialist Party (PSB), Communist Party of Brazil (PC do B), Brazilian Progressive Party (PPB), Popular Socialist Party (PPS), Green Party (PV), the Social Liberal Party (PSL), the National Mobilization Party (PMN), National Workers Party (PTN), Humanistic Solidarity Party (PHS), and the Party of the Reedification of the National Order (PRONA).

Brazil Government and Political Conditions
Brazil is a federal republic with 26 states and a federal district. The 1988 constitution grants broad powers to the federal government, made up of executive, legislative, and judicial branches. The president holds office for 4 years, with the right to re-election for an additional 4-year term, and appoints his own cabinet. There are 81 senators, three for each state and the Federal District, and 513 deputies. Senate terms are 8 years, staggered so that two-thirds of the upper house is up for election at one time and one-third 4 years later. Chamber terms are 4 years, with elections based on a complex system of proportional representation by states. Each state is eligible for a minimum of 8 seats; the largest state delegation (Sao Paulo's) is capped at 70 seats. This system is weighted in favor of geographically large but sparsely populated states.
source: http://www.state.gov