The current structure of the Brazilian government was set up by the Constitution of 1988, written as the country returned to full democracy following a more than two-decade-long military dictatorship.

At the Federal level, power is divided between the Executive, Legislative, and Judicial Branches, similar to the divisions used in the United States.

The Executive is headed by a President, who can be elected to two consecutive four-year terms (non-consecutive terms are not limited). There is also a Vice President, elected along with the President, and a Cabinet of Ministers which are appointed.

The Congress, also similar to the United States, is bicameral with a Senate and a Chamber of Deputies. Each state has three senators, and these are elected to eight-year terms. The election of Senators is staggered, with one-third of the Senate being elected in one election year, and two-thirds in the next (in 2010, two-thirds of the Senate will be elected). Deputies are allocated to the states based on population (although small states are overrepresented, as explained below), and serve terms of four years. There is no term limit for either House of Congress.

Deputies are not elected to represent a district as in the United States, but are proportionally assigned based on the total vote within a state. This allows a great number of minority parties to achieve representation in Congress. Because the proportions are party-based, however, this means that independent or write-in candidacies are disallowed - all candidates must be members of a political party. In order to fairly proportion the vote in small states, the minimum number of deputies per state is eight. This does cause an overrepresentation of small states among the 513 total federal deputies.

All 27 state governors are elected at the same time and are limited (as with the Presidency) to two consecutive four-year terms. State Legislatures are all unicameral and their members are proportionally elected in a procedure similar to that for Federal Deputies.

Therefore, in 2010, all of the following offices are up for election:

President/Vice-President

54 of 81 Senators (2/3)

All 513 Federal Deputies

All 27 Governors/Vice-Governors

Members of all 27 State Legislatures

Unlike the District of Columbia, the Federal District of Brazil (containing the city of Brasília) has full voting rights in Congress, and is included as one of the 27 states.

In off-year elections, such as 2008, 2012, etc., mayors and city-council members are elected.

Because of the nature of proportional representation, a robust multi-party system has sprung up in Brazil over the past quarter century. At last count, 22 political parties are represented in Congress, and it can be quite a difficult job to attempt to disentangle these competing factions and figure out exactly where they fit on the political/ideological spectrum. However, a few of them will be mentioned here.

Worker's Party (PT): This is the traditional leftist party, though they are more often thought of in recent years as center-left. It is the party of incumbent President Lula da Silva and controls the second-largest bloc in the Chamber of Deputies. Their move towards the center in 2002, as well as the emergence of various scandals in the following years, led to the creation of a splinter party on the left, known as PSOL (Socialism and Liberation Party).

Brazilian Democratic Movement Party (PMDB): This is the traditional centrist party, and the one which controls the largest bloc of Deputies as well as the largest number of governors. During the military dictatorship, it was the "approved opposition" - the only party allowed as an alternative to the ruling ARENA group. They are the party of Tancredo Neves, elected in 1985 to be the first president following the military dictatorship (but who died before taking office). It is currently allied with Lula's PT (Michel Temer is running for vice-president on Dilma Rousseff's ticket), and is known as a party of opportunism. In recent elections, they have chosen not run a presidential candidate, but have focused on state and congressional elections, shifting alliances frequently to always be on the side of whoever has the most power (while currently allied with Lula, they sided with his opponent Serra and the PSDB in 2002).

Brazilian Social Democratic Party (PSDB): This is today the strongest center-right party, though it was originally founded as a less radical left-center alternative to PT. It is the party of former President Fernando Henrique Cardoso (1994-2002), and shifted strongly rightward during his presidency. Their current candidate for president is José Serra, former São Paulo State Governor, who is running for the second time (having lost in 2002).

Democrats (DEM): No, not the Democratic Party, just "Democrats." This party was known until 2007 as the Liberal Front Party, but don't let the names fool you: it has always been the largest of the far-right parties in Brazil. It is a direct descendent of the ARENA party of Brazil's military dictatorship and still maintains a large bloc in Congress. However, it lost 20 seats in 2006 and all but one state governorship, and its prospects do not look promising for 2010.

Next diary: a brief analysis of some of the most important races at stake in 2010.