Brazil's top electoral court on Wednesday returned to its examination of illegal campaign finance allegations that could force President Michel Temer from office, with much hinging on whether the judges throw out testimony that arose from plea bargains.

Defense attorneys were trying to exclude the damaging testimony against Temer and former President Dilma Rousseff by executives at the huge construction company Odebrecht. It is one of the businesses at the center of a sprawling investigation into kickbacks and bribes at the state-run oil company Petrobras, a scandal that has upended Brazilian life.

A simple majority among the seven judges will decide the question.

If the testimonies are allowed, Temer would be one step closer to being pushed out of office over allegations that the Rousseff-Temer ticket in 2014 was backed by illegal campaign contributions. Rousseff, who was impeached last year for illegally managing the government's budget and replaced as president by Temer, could lose her right to hold office for eight years.

Judge Herman Benjamin, who was named by the court to examine the case, began proceedings Tuesday evening with his analysis of the charges against the Rousseff-Temer campaign.

Hermann said the trial would be "based on facts, not on political convenience."

Rousseff asserts innocence as does Temer, who argues that his team was not responsible for fundraising.

The trial was expected to take at least three days, and there is no deadline for a final ruling by the seven judges. It is the first time in Brazil's history that a sitting president has risked having the job taken away by the electoral court.