* Congress has frenzy of activity, Rousseff plans plebiscite
* Demonstrators demand better services, corruption crackdown
* Protests could re-ignite if changes are slow in coming
The massive protests that paralyzed Brazil last week appear to have peaked after sending the country's shaken political establishment a loud message that it needs to change its ways.
It's now up to the politicians to deliver improvements to the country's deficient public services and more transparent and accountable government demanded by frustrated Brazilians, or the crescendo of angry protests could suddenly return.
While smaller protests continue on a daily basis, the number of demonstrators this week was much lower than the one million people who took to the streets a week ago, due to a mix of protest fatigue and achievement of the protesters' initial aim of drawing attention to their grievances.
Tens of thousands may still protest around Sunday's Confederations Cup final soccer match between Brazil and Spain in Rio de Janeiro, the locus of violence so far, but the end of the soccer tournament will deprive protesters of a high-profile stage on which to air their grievances.
"The streets are saying to the politicians: you have heard our voices, now let's see what you will do with this," said Marcos Nobre, a political philosophy professor at the University of Campinas and author of a new e-book on the popular revolt.
"The protests have peaked but they are not over. This is a truce as Brazilians wait to see how the political system responds," Nobre added.
Politicians in Brasilia are rushing to clean up their act to appease the anger directed at them by the protesters. Congress is fast-tracking measures against corruption. One of its members, convicted of embezzling public funds, on Friday became the first federal lawmaker to go to jail in 25 years.
But analysts say deeper reforms will be needed to restore public credibility in a political class viewed as self-serving, overpaid and corrupt.
The civil unrest, something rarely seen in recent decades in South America's economic powerhouse, was sparked by a small protest against higher public transportation fares in Sao Paulo.
The ensuing police crackdown, which touched a nerve in a country with a history of violent political repression under a military dictatorship that ended in 1985, fanned demonstrations nationwide even after cities agreed to roll back the fare increases.
The protests were fueled by widespread frustration with Brazil's deplorable education, health and transportation services, rising crime and cost of living, as well as over-spending on stadiums that will host next year's World Cup soccer tournament.
Six people died in the protests, including a young man who fell from an overpass in Belo Horizonte on Wednesday as riot police fired tear gas and rubber bullets into marchers to stop them from reaching a stadium where a Confederations Cup game was underway.
The Confederations Cup is a warm-up for the 2014 World Cup, which Brazil will host in 12 cities.
The protesters used the Confederations Cup to tell the world that Brazil is not just a land of soccer and that their priorities are improved education, healthcare and public transportation rather than costly mega-events like the World Cup and the Olympic Games set for 2016 in Rio de Janeiro.
TAKEN BY SURPRISE
The protests took Brazilian politicians by surprise and showed how out of touch they were with an increasingly middle-class nation that is more informed and unwilling to tolerate a political system long plagued by patronage and corruption.
The leaderless protests expressed a wide array of demands, but one common target, Nobre said, was "a corrupt political system that does not represent this new democratic political culture that has arisen mainly through social networks."
The protests sent shockwaves through Brazil's Congress and prompted frenetic activity by lawmakers who have rushed to pass legislation that had been sitting around for years, notably a bill toughening sentences for corruption.
"The political class fears the consequences of this popular revolt. Politicians are keenly aware that if we do not change the way we do things we are going to be trampled on in next year's elections," Alvaro Dias, leader of the opposition PSDB party in the Senate, told Reuters. "Congress is making up for lost time by rushing through bills."
President Dilma Rousseff has received scant praise for her response, even within her own party, and elections are coming.
Brazil's first female president is expected to run for a second term next year and her popularity had already begun to slip before the protests on concerns about rising inflation and slow growth in the world's seventh-largest economy.
Rousseff surprised Brazil on Monday by announcing plans to convene a constituent assembly to adopt political reforms. Within less than 24 hours, she had withdrawn the idea in the face of strong criticism even from within her ruling coalition.
Her Workers' Party government is now working with its allies to hold a quick plebiscite this year that will ask Brazilians what political reforms they want, a plan that is seen as overhasty damage control by opposition leaders such as Dias.
Even members of her unwieldy 16-party coalition would rather Congress draw up the reforms first and then seek the nation's approval in a yes-or-no referendum that could be added to the ballot in the general election slated for October 2014.
If the response to the protests is unsatisfactory for Brazilians, the protests would re-ignite, Nobre said. And if they continue into 2014 they could endanger the holding of the 32-nation World Cup - an ideal occasion for new demonstrations - and disrupt campaigns of politicians seeking re-election.
Socialist lawmaker Chico Alencar says the survival instinct of Brazil's politicians has made them react quickly to the loud criticism from the streets, but changes modernizing Brazil's democratic system will come only if popular pressure continues.
"If the protests fizzle out, conservative forces that want to maintain the status quo will regain control of the political agenda," he said.