The Mensalão scandal (Portuguese: Escândalo do Mensalão, IPA: [isˈkɐ̃dɐlu du mẽsɐˈlɐ̃w̃]) was a vote-buying scandal that threatened to bring down the government of Luiz Inácio Lula da Silva in 2005.Mensalão is a neologism, a variant of the word for "big monthly payment" (salário mensal or mensalidade).
The scandal broke on June 6, 2005 when Brazilian deputy Roberto Jefferson told Folha de S.Paulo that the ruling Partido dos Trabalhadores (PT) -- usually translated as Workers' Party—had paid a number of deputies 30,000 reais (around US$12,000 at the time) a month to voting in favor of legislation favored by the ruling party. The funds allegedly came from state-owned companies' advertising budgets, funneled through an advertising agency owned by Marcos Valério. The investigation has since uncovered members of the Brazilian Social Democracy Party, DEM, Brazilian Democratic Movement Party and seven other political parties also involved. Many key advisers to Lula resigned, and several deputies were faced with the choice of resignation or expulsion from congress, though the president himself went on to be re-elected in 2006, and in 2010 Brazil elected his chief of staff, Dilma Rousseff, as president. Much of the PT's leadership was affected in some way, with many resigning or failing to win re-election. Brazil's economy was widely perceived as not having been substantially impacted by the scandal.
Roberto Jefferson, who initially sparked the scandal, was expelled from the Chamber of Deputies on September 14, 2005 for ethical violations determined by the Congressional Council of Ethics. Despite continued resignations, in October the scandal died down somewhat as Brazil held a contentious referendum on a banning gun sales, an initiative soundly rejected by voters.