Reversals of fortune do not come much sharper or more symbolic than that suffered by Dilma Rousseff over the past year.

Last December, she was still in the early stages of her second term as Brazil’s first woman president. Unbeaten in elections, she lived in a palace, commanded Latin America’s biggest bureaucracy, joined summit banquets alongside Barack Obama, Vladimir Putin and Angela Merkel, and went on her morning bicycle ride in Brasília with the full protection given to a head of state.

Today, however, after being levered from power by her running mate and impeached by Congress, Rousseff lives in her mother’s apartment, buys her own groceries at the local supermarket, has a one-man security detail and rides her bike along the seafront of Rio de Janeiro with the rest of the crowd.

There can be few more striking personifications of the demise of the political left in the past 12 months. But even though it may seem that the world has moved backwards in terms of gender, race and income equality, Rousseff – who has arguably lost more than anyone – says that for her, this is by no means rock bottom.

“Every day has been difficult,” she tells the Guardian during an interview near her residence in Rio de Janeiro. “But this is not the worst year I have experienced. Not at all.”

That distinction belongs to the period 1970-1972, when she was imprisoned and tortured for belonging to a clandestine Marxist guerrilla organisation that was committed to overthrowing the military dictatorship. She suffered beatings, electric shocks and other forms of abuse without ever giving up the names of her collaborators.

In comparison, she said, even the bleakest moments of the past year have been bearable.

Among the worst was on 17 April, when her fate was effectively sealed by a rowdy lower house impeachment vote. Her alleged wrongdoing – window dressing government accounts – was far less severe than the accusations faced by more than 100 of the deputies who rose in judgment against her, but she was damned nonetheless, putting her on a course that later led to her removal from the presidency and the negation of the 54m votes that put her in power.

How did she feel that night? “It’s hard to say. There is such a kaleidoscope of memories,” she says, pausing at some length to find the right words, “I felt sadness, despair and indignation.”

Expressions of emotion do not come easily to Rousseff in sharp contrast to her Workers’ party mentor and predecessor as president, Luiz Inácio Lula da Silva. The two of them watched the impeachment vote together on a TV in the presidential palace. While he sobbed, she ordered popcorn.

“He cried, and he hugged me, and he said to me ‘cry Dilma, cry!’ But I don’t cry when I’m moved. That’s not how I am,” Rousseff said. Asked if she had always been like that or whether it was a mental hardening that occurred during her torture, the former prisoner pauses again.

“I think it goes back to that time. You can break at any moment so you have to keep fooling yourself. You have to keep kidding yourself that it’s nearly over or else you fold. You tell yourself, it’s just 10 more minutes. Then, 10 minutes later, you persuade yourself it’s just another 10.”

Those old scars were reopened during the impeachment debate by ultra-right deputy Jair Bolsonaro, who dedicated his pro-impeachment vote to the military dictatorship – specifically to the army colonel who tortured Rousseff.

“I was shocked he could say that in congress,” she recalls. Bolsonaro, who plans to stand for the presidency himself in 2018, was never punished for his comments – a sign of both the impunity and the conservatism that characterise Brazil’s congress.

Rousseff believes misogyny is partly to blame for her downfall, as well as the election defeat in the United States of Hillary Clinton – who the Brazilian describes as a “friend despite our differences”. As she has noted on numerous occasions, there are double standards for women politicians, who tend to be called “hard” rather than “strong” when they take tough decisions.

“The fact that I was the first woman president was a factor in what happened to me. It is hard to quantify. It wasn’t 100% because of that. But it was a component,” she says. “I think it will be easier for the next woman president.”

Her critics say she brought about her own downfall. Enemies on the right say she ruined the economy (now in its deepest recession for decades). The disaffected on the left believe her budget cuts were a betrayal of her election promises. Many across the political spectrum suspect that she knew about – and politically benefited from – a massive bribery and kickback scheme at the state-run oil giant Petrobras, even if she wasn’t directly involved or personally enriched.

Even allies who praise her for being unusually honest and well-intentioned admit she tends to be secretive and a dire communicator.

Freed from the responsibility of office, Rousseff is now more loquacious. She appears to be on a mission to clear her name. The senate acknowledged her relatively modest individual guilt by not stripping her of her political rights after ejecting her from office on 30 August. But she wants her side of the story told and – like Lula – has probably granted more interviews in the past few months than in the previous five years.

She blames Brazil’s dire economy on a global storm of falling commodity prices, weakening Chinese demand, a debilitating drought and the after-effects of the 2008 financial crisis.

Behind the political turmoil, she sees a cabal of plotters – led by current president Michel Temer, her former deputy who she says engineered her downfall, and former lower house speaker Eduardo Cunha – who have dragged the traditionally centrist Brazilian Democratic Movement party to the right. Allied to oligarchical interests in the financial sector, she said they turned against her with greater strength after she cut real interest rates for the first time in more than a decade and achieved almost full employment.

Complicating the whole situation, she says, is the increasing fragmentation of political parties, which has created a climate for corruption. In the 1990s, thenpresident Fernando Henrique Cardoso needed the support of only three parties to secure a simple majority in congress. In the following decade, Lula had needed eight. By the time Rousseff left office, this had increased to 12.

“It’s every day. Everything is a negotiation. It’s the only way to get power,” she said. “People say I don’t like politics, but that is not true. What I don’t like is the buying and selling … It’s always existed, but not to this degree.”

This is somewhat disingenuous. Rousseff was at the apex of this system for close to a decade, first as chief of staff for Lula and then as president. Unlike many of her accusers, she may not have gained personally (as she says, “I don’t have secret Swiss bank accounts, I didn’t rob anything”) but she was unwilling or unable to push a meaningful clear-up on her party and coalition allies. Instead, she left prosecutors and the courts to do the job, while focusing her government on its social and political goals.

Asked if she regretted winning in 2014 – just as this system started to come crashing down along with the economy – Rousseff shakes her head. “Not for one moment. If I hadn’t won, things would be much worse now. We would already have an austerity and privatisation package like that of [President Mauricio] Macri in Argentina.”

Although she credits her short-lived second administration for delaying and reducing the impact of the neoliberal tide now sweeping Latin America, she is not optimistic about the near-term prospects for progressive politicians in Brazil or elsewhere. Brexit and the election of Donald Trump are, she says, a cause for wider concerns.

“With the increase once again of inequality, especially in developed countries, it creates the conditions for disbelief in democracy. If the demands of the population cannot be met by governments, then politics becomes irrelevant. Then, it won’t be projects or proposals, or even utopias, that will move people. Instead, people will focus on symbols, slogans and scapegoats. That’s when the right rises and intolerance grows.”

For most of her life, Rousseff has been fighting these trends. But for now, she plans to step back and study her enemy. Her immediate plan is to research the concept of “states of exception” – the term coined by Nazi jurist Carl Schmitt to justify dictators who bypass national laws in the name of the public good.

With these justifications creeping back – for example with the Patriot Act in the US, the criminalisation of the poor and the treatment of refugees – Rousseff says the memoirs will have to wait.