By Fernando Cardoso, Ricardo Brito and Lisandra Paraguassu
SAO PAULO/BRASILIA, Oct 5 (Reuters) - Brazil's right-wing Liberal Party, home to Senator Flavio Bolsonaro's presidential bid, emerged as the biggest winner in congressional elections on Sunday, securing the largest single-party representation in both the Senate and the lower house.
Senator Bolsonaro, the eldest son of former President Jair Bolsonaro, on Sunday won the most votes in the first round of the presidential race, advancing to a runoff
against leftist President Luiz Inacio Lula da Silva on October 25.
During the campaign, the younger Bolsonaro stumped often for allied Senate candidates. His Liberal Party (PL) increased its representation in the Senate from 15 to 28 seats, the strongest result for a party since Brazil's return to democracy in 1985. It also secured 121 seats in the lower house, projections for that chamber showed, up from 98 seats currently.
Combined with other center-to-right parties and blocs, who were projected to win close to 250 seats in the lower house and more than 30 seats in the Senate, the Bolsonaro agenda looks set to enjoy a healthy working majority in the next Congress.
An allied Congress - and particularly Senate - would help the younger Bolsonaro achieve his aim of granting amnesty to his father, who is serving a 27-year sentence for plotting a coup after losing the 2022 election.
The Senate's pro-Bolsonaro bloc may even be close to the threshold of 54 votes needed to impeach the Supreme Court justices who convicted the far-right former leader.
"I was very happy to see how many Brazilians went to the polls to make their voices heard and didn't stay on the sidelines because they want change," Bolsonaro said after the vote.
Sunday's legislative races, held alongside the first round of the presidential election, renewed all 513 seats in the lower house of Congress and two-thirds of the 81-seat Senate.
Congressional races in Brazil have drawn increasing voter attention in recent elections as lawmakers expand their influence in the capital Brasilia, particularly through greater control over federal spending and leverage over presidential appointments.
Lula's Workers Party (PT) also increased its footprint in Congress. The party maintained its Senate presence with nine seats, and a three-party bloc led by the PT was projected to win 88 seats in the lower house, up from 82 currently.
GOVERNANCE CHALLENGES
Even as Lula fights for a come-from-behind victory in the second round of voting, analysts say the next Congress would make his fourth, non-consecutive term an uphill battle.
"Governance would pose a major challenge for President Lula," said Neuriberg Dias, head of legislative watchdog DIAP, adding that a right-wing bloc would work to stifle legislative progress and the functioning of government.
Both political camps have illustrated the difficulties faced by presidents who do not have sufficient congressional backing.
In April, Lula became the first Brazilian president in more than a century to see a Supreme Court nominee voted down amid tensions with center-right Senate President Davi Alcolumbre.
Congress has also overturned dozens of Lula's vetoes since his return to office in January 2023, underscoring lawmakers' growing assertiveness.
Former President Bolsonaro faced similar obstacles, with Congress blocking some of his most prominent policy initiatives, including efforts to loosen gun-control rules and introduce a printed ballot verification system for elections.
(Reporting by Fernando Cardoso in Sao Paulo, Ricardo Brito and Lisandra Paraguassu in Brasilia; Editing by Brad Haynes, Oliver Griffin and Chizu Nomiyama)
