Judge Herman Benjamin, who was named by the court to examine the case, began with his analysis of the charges against Temer, but left his vote for the next session Wednesday morning. The hearing was expected to take at least three days, and there is no deadline for a final ruling by the seven judges in the case, which is the first time in Brazil's history that a sitting president risks could have the job taken away by the electoral court.
The suit was brought after the election by the right-leaning Brazilian Social Democracy Party, whose presidential candidate, Aecio Neves, lost to the ticket of then President Dilma Rousseff and Temer as her vice presidential running mate. Ironically, the party has been a key ally of Temer since he took over the presidency after Rousseff was suspended and then impeached last year.
If the court decides the Rousseff-Temer ticket did receive illegal campaign financing, as several plea bargains have suggested, Temer mandate would be annulled and Congress would have to pick some to serve out his term through December 2018. However, the career politician whose popularity is hovering around 8 percent has said he would appeal.
Rousseff claims innocence as does Temer, who argues that his team was not responsible for the fundraising of the ticket. Amid growing pressure for the president to resign amid a number of different corruption allegations, Hermann said this trial will be "based on facts, not on political convenience." Supreme Court Justice Gilmar Mendes, who presides over the electoral court, described the trial that could remove his old friend as "a great learning experience."
If Temer is eventually pushed out of the presidency by the court, or decides to resign, Chamber of Deputies Speaker Rodrigo Maia would take over for 30 days while Congress voted in a new leader. The electoral court scheduled more sessions for Wednesday and Thursday, but those could be postponed if any of the seven judges asked to review the case.
On Wednesday, the court will have to analyze a preliminary issue that could change the proceedings: Both Rousseff's and Temer's legal teams want the judges to reject information coming from plea bargain testimony from executives of the giant construction company Odebrecht, which is caught up in the sprawling investigation into bribes and kickbacks involving Brazil's state-run oil company Petrobras. They argue that accusations made by Odebrecht employees involving the 2014 campaign exceed the original scope of the Petrobras investigation.
Mauricio Santoro, a political analyst at Rio de Janeiro State University, said he expects the court to postpone a final decision in the case or find a way to separate Temer from Rousseff's ticket. "Temer has built a coalition of supporters in the Supreme Electoral Court under the argument that people may not like him, but there's no consensus about who his successor should be," Santoro said.
Hours before the trial began, Temer's political situation deteriorated further with the arrest of a former tourism minister and close ally. Henrique Eduardo Alves was taken into custody on allegations of corruption related to the construction of a 2014 World Cup stadium in Natal.
Globo News captured images of Alves being arrested by federal police. Officials held a news conference later at which they laid out allegations that Alves and Fred Queiroz, Natal's secretary of public works, received bribes from major construction companies.
Alves, a former speaker of the Chamber of Deputies, was tourism minister under both Rousseff and Temer, who assumed the presidency last year when Rousseff was removed for illegally managing the federal budget. Alves gave up the Cabinet post soon after Temer took power in May 2016.
His arrest came just a day after federal police sent Temer a list of questions in a separate criminal probe that involves the president. He had 24 hours to answer the questions, but his lawyers got an extension until Friday afternoon.
Last month, Brazil's top prosecutor opened investigations on Temer for alleged passive corruption and obstruction of justice. Temer is being investigated for allegedly endorsing the payment of hush money to former Chamber of Deputies Speaker Eduardo Cunha, another former ally. Cunha is serving a 15-year prison sentence for corruption and money laundering.
The president is also being investigated for allegedly receiving bribes via former aide Rodrigo Rocha Loures. On Tuesday, Brazil's top court rejected a petition by Loures to be released from jail. Loures was arrested over the weekend. Police released video that apparently showed Loures carrying a suitcase filled with $154,000. Should he reach a plea bargain, his testimony could further implicate Temer.
Temer has denied wrongdoing and has vowed to stay in office in the face of increasing calls for him to step down.
Associated Press writers Liliana Michelena and Peter Prengaman in Rio de Janeiro contributed to this report.
Mauricio Savarese on Twitter: twitter.com/msavarese