RIO DE JANEIRO -- The approval rating of Brazil's president, Dilma Rousseff, plunged in June to 30 percent from 57 percent, reflecting swelling anger against the government since protests spread to more than 100 cities in recent weeks in a broad repudiation of political corruption, deplorable public services and costly stadium projects for the 2014 World Cup.
A poll released on Saturday by Datafolha, a leading Brazilian research company, ratchets up pressure on Ms. Rousseff, 65, to respond more energetically to the concerns of protesters, and raises doubts over what might happen in next year's presidential election. Until the unrest, she enjoyed resiliently high approval ratings, which made her a favorite to win re-election.
More than 80 percent of respondents in the Datafolha poll, which had a sampling margin of error of plus or minus two percentage points, expressed support for the protests.
The poll also showed that support for Ms. Rousseff -- an economist who has been trying to stir Brazil's sluggish economy with huge stimulus projects -- eroded even in bastions of support for the governing Workers Party, like northeast Brazil. Her approval rating there fell to 40 percent from 64 percent at the start of June, when the protests began escalating.
Political rivals have been increasing their criticism of her response to the protests, which has included proposals to hire thousands of foreign doctors to strengthen the public health system, channel oil royalties to education projects and hold a nationwide vote on reforming the political system. Ms. Rousseff herself has voiced some support for the protests, while also warning against the violence that has marred demonstrations.
"She spoke more than listened," Marina Silva, a former environment minister who placed third in the 2010 presidential election, said in an interview with the newspaper Estado de São Paulo. "It was obvious that doing a marketing-focused discourse wasn't going to work."
The Datafolha poll, conducted on June 27 and 28 in a survey of 4,717 people, put Ms. Rousseff's government on the defensive.
"She recognizes there's a change and thinks that the remedy is to work a lot," Paulo Bernardo Silva, the communications minister, said after meeting with the president on Saturday. He said that the authorities planned to continue discussions with representatives of the protests, which have criticized a broad range of political leaders, in an effort to identify priorities.
Outside the executive branch, other institutions have also been scrambling to react to the protests. In a remarkable development, the federal police on Friday took into custody Natan Donadon, a legislator convicted in 2010 on corruption charges, after the high court ordered his arrest. It is rare for members of Brazil's Congress to ever serve prison time for corruption convictions, making the legislature a prominent object of ire and derision for protesters.
The authorities are bracing for more protests, including a large demonstration planned in Rio de Janeiro for Sunday near Maracanã, the stadium where the national teams of Brazil and Spain are set to play. Brazilian news organizations reported that Ms. Rousseff canceled a plan to appear at Maracanã; she and Joseph S. Blatter, the president of FIFA, soccer's governing body, were booed this month before a game between Brazil and Japan.world
This article originally appeared in The New York Times.