Brazil`s first female president, a moderate leftist, is accused of illegal budgeting maneuvers, but says the practices were long accepted by previous governments. She calls the attempt to bring her down a "coup."
Rousseff is fighting for her political life just one year into her second term at the head of the world`s seventh biggest economy.
The commission is charged with studying the case, then making a recommendation to the lower house of Congress, where a two-thirds vote would be required to put Rousseff on trial in the upper house and possibly force her from office.
The unrest is stirring passions across the South American country of 204 million people, where Rousseff`s Workers` Party has been in power since 2003 with the help of its often uncomfortable partner the centrist PMDB.
Deputies either in open opposition or part of the ruling coalition yet favoring impeachment took 39 of 65 seats on the newly formed commission after a chaotic voting process that erupted in shouting and pushing.
This did not bode well for Rousseff, who on paper has the numbers between her Workers` Party and main coalition ally PMDB to survive.
However, those calculations were thrown into doubt with the publication overnight of an angry letter from PMDB leader and Vice President Michel Temer in which he all but announced their political divorce.
Temer told the president that during her first term in office starting in 2011 he was reduced to a "decorative" role and that she has shown an "absolute lack of confidence" in him.
If Rousseff is forced from office, Temer would become interim president.
The turmoil has alarmed markets, already bruised by recession and a huge corruption scandal centered on state oil company Petrobras. Andre Perfeito, chief economist at Gradual Investimentos, referred to a "climate of war."
`Terrible start`
Rousseff`s chances of survival remain unclear, but she has come out swinging, calling on Congress to speed up proceedings and to scrap the annual holidays that run from December 23 through to February.
She got one bit of good news Tuesday when 16 of the country`s 27 state governors declared that the impeachment case lacks constitutional "foundation."
Michael Mohallen at the Getulio Vargas Foundation, said "it`s still early to say this is the beginning of the end for Rousseff."
But Rubens Figueiredo, a politics professor at the University of Sao Paulo, said she had been left weakened Tuesday. "It was a terrible start for the government," he said.
Both sides of the debate have promised to take to the streets in an attempt to pressure Congress during what could potentially turn into months of intrigue if the impeachment procedure goes the full course.
In Rio de Janeiro, several hundred trade union activists marched in support of Rousseff late Tuesday, at one point letting off a deafening barrage of crackers that spewed orange smoke into a central avenue. Opposition groups have announced nationwide rallies for Sunday.
Unpopular president
Rousseff has approval ratings of about 10 percent and is widely blamed for a devastating economic slump.
Brazil, host of the 2016 Rio Olympics, is in a deep gloom, with GDP down 4.5 percent in the third quarter year-on-year, and the national currency down a third against the dollar this year.
Also tainting Rousseff is the Petrobras scandal, which has sucked in leading politicians and business figures, exposing the depth of corruption at the highest levels in Brazil.
Ironically, Rousseff herself has not been linked to any Petrobras-related crimes, while the chief architect of the impeachment drive, the PMDB`s Eduardo Cunha, who is house speaker, is accused of taking millions of dollars in bribes.
Cunha faces being ejected from his speaker`s post by the house ethics committee and is widely accused of having used the impeachment battle as a way of taking revenge against the government and prolonging his own influence.
Mohallen said Cunha had shown his "organizing powers at a time when one thought he was a (political) living dead."
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