Addressing the Senate that will rule on whether to dismiss her from office, Dilma Rousseff says her opponents are trampling on democracy by using trumped-up charges to oust her.
She's denied breaking budgetary rules by using money from state banks to boost public spending.
"I am going to look directly in the eyes of Your Excellencies. I will say with the serenity of someone who has nothing to hide that I haven't committed any crime against the budget and these accusations are unfair."
Ms Rousseff says the impeachment process, which has paralysed Brazilian politics for nine months, is a plot to protect the interests of the county's economic elite.
Brazilians are divided on the impeachment issue.
Some say they believe Brazil's first female president should be forced to leave office, while others, like this man, say she should be allowed to finish her second term.
"Should we kick out the president just because she has been doing wrong or Brazil has been going in the wrong direction? I don't think so. She is an elected president, so we should let her stay until the end of her term."
A group of about 200 supporters of Ms Rousseff gathered outside the Senate.
Among them was this man, who got emotional while talking about the 68-year-old's potential removal from office.
"I would feel devastated. I would feel that we have such a long way to go again. Oh, it's terrible. We were going forward as a country. We are moving backwards really fast now."
The Senate's 81 senators are expected to hold a final vote tomorrow.
If it goes against Ms Rousseff, her vice president, Michel Temer, who has been interim president since mid-May, will be sworn in to serve the rest of her term.
If Ms Rousseff is acquitted, she will immediately return to office.
