Tom Phillips in Rio de Janeiro
guardian.co.uk, Wednesday 19 August 2009 17.36 BST
Brazil's former environment minister, the rainforest defender Marina Silva, has resigned from the ruling Workers' party, paving the way for a 2010 presidential bid, which supporters hope will put the environment back on the political agenda of South America's largest country.
For weeks speculation has been growing that Silva, who resigned from government last May after a dispute over the development of the Amazon region, would defect to the Green party in order to dispute the presidential elections next October.
Speaking at a press conference in Brasilia earlier today, Silva, who has been a Workers' party member for over 30 years, said politicians had failed to give sufficient attention to the environmental cause.
In her resignation letter to the president of the Workers' party, Silva said her decision was an attempt to break with the idea of "development based on material growth at any cost, with huge gains for a few and perverse results for the majority" including "the destruction of natural resources".
She added that "political conditions" had meant that "environmental concerns had not been able to take route at the heart of the government."
Silva, 51, stopped short of formally announcing a presidential bid but few doubt that she will now front the Green Party's 2010 election campaign.
The Brazilian media has been overtaken with Marina mania since earlier this month when rumours about a possible bid for the presidency began spreading. This week one major news magazine stamped Silva's photograph onto its front-page alongside the headline: "President Marina?"
Writing in the O Globo newspaper yesterday, the influential columnist Zuenir Ventura said Silva could bring a touch of Barack Obama to the Brazilian elections.
"Marina excites young people, those who are disenchanted with the current situation [and] with the Workers' Party … in such a way that she could create a spontaneous and contagious movement within society … as innovative as that which occurred in the US with Obama," he wrote.
Born in an impoverished community of rubber tappers in the remote Amazon state of Acre, Silva was orphaned at 16 and was illiterate until her early teens.
In 1994, aged 35, she was elected as Brazil's youngest ever female senator and subsequently became renowned for her staunch defence of the Amazon rainforest and its inhabitants, winning a succession of international awards for her work. The president, Luiz Inácio Lula da Silva, has not so far commented on her resignation.