BRASILIA (BBC) -- Brazil's marathon election campaign has formally begun, giving voters three months to assess the candidates before going to the polls in October.

They will elect a president, state governors, and members of Parliament.

President Luiz Inacio Lula da Silva is fighting for a second term, one year after a bruising corruption scandal.

Opinion polls have shown his popularity is up, but much depends on the performance of Geraldo Alckmin of the Brazilian Social Democratic Party.

Less than a year ago, many commentators were writing the political obituary of President Lula. --------Comeback kid

His workers' Party had admitted raising millions of dollars in illegal funds, and although the president himself avoided blame, the scandal brought down some heavyweight members of his government.

A year on and President Lula looks to be making a comeback.

The economy has taken an upturn and 40 million poorer Brazilians are benefiting from Bolsa Familia, a welfare program that is slowly reducing the country's gaping inequalities.

The opinion polls are predicting a comfortable win for the president, possibly in the first round of voting on 1 October.

Much depends now on the campaign performance of his main opponent, Geraldo Alckmin of the Brazilian Social Democratic Party.

Alckmin was a solid reliable governor of Sao Paulo but he lacks the charisma of Lula and he is little known outside his home state.

He insists that free television airtime will boost his popularity and in recent weeks the challenger has begun to close the gap in the polls.

That suggests October's result is by no means a foregone conclusion, and in a country notorious for political surprises, three months of campaigning is an eternity.

The performance of Brazil's economy will influence this race, as will the issue of corruption. In the coming weeks expect both main parties to dredge up new allegations. (Lula)