Impeachment trial of Philippine VP Sara Duterte to open in divided Senate

Highlights:

• Senate to sit as impeachment court from Monday
• Important that public has confidence in process given sharp political divisions, analysts say
• Duterte denies wrongdoing and says her impeachment is politically motivate

The impeachment trial of Vice President Sara Duterte, which begins on Monday, is set to frame the Philippines 2028 presidential race and deepen a schism between two storied political dynasties that has plunged the Senate into turmoil.

The outcome will not only determine whether Duterte could run for the presidency, it will also test confidence in the Southeast Asian nation's institutions and politicians. Analysts say the key will be whether the public sees the verdict as credible or instead driven by partisan interests.

"If it is seen as politically motivated or lacking credibility, questions may linger regardless of the outcome," said Ederson Tapia, a public administration professor at the University of Makati.

It remains unclear how long the trial will last, with factors such as procedural disputes, the number of witnesses and the presentation of evidence likely to determine its pace. The impeachment trial of a former chief justice in 2012 lasted four months. A conviction requires the votes of at least 16 of the Senate's 24 members. Opinion polls show Duterte is a leading contender for the 2028 election, but a guilty verdict could jeopardise her presidential ambitions.

"If the public perceives the process to have been fair, an acquittal could strengthen her position," Tapia said.

The first impeachment trial of a vice president centres on allegations that Duterte misused public funds, amassed unexplained wealth and threatened the lives of President Ferdinand Marcos Jr, the first lady and a former House Speaker.

Duterte, the daughter of former President Rodrigo Duterte, denies wrongdoing and insists the impeachment is politically motivated.

"That is to be expected," Congressman Robert "Ace" Barbers, spokesperson for the prosecution, said of the vice president's assertions. "We will let the evidence speak for itself."

Jean Encinas-Franco, a political science professor at the University of the Philippines, said both sides must be able to properly present their case to ensure public confidence.

She cited the impeachment proceedings against then President Joseph Estrada, in which a Senate vote to withhold key evidence triggered public outrage, halted the trial and fuelled mass protests that led to Estrada's removal from office in January 2001.

"They really have to make sure that both the prosecution and the defence are given enough time and voice … so the public does not perceive the trial as favouring one side," she said.

Duterte's lawyer, Michael Poa, said the defence was prepared to prove the allegations were "baseless". He could not yet say whether Duterte would attend Monday's proceedings, as the summons said she could be represented by counsel.

Joint ticket to bitter split

Marcos and Duterte, heirs to two of the country's most powerful political dynasties, ran on a joint ticket in 2022. Their alliance has since unravelled in an increasingly bitter feud that deepened after Rodrigo Duterte's arrest and transfer to International Criminal Court custody in March last year.

The schism has spilled into the Senate, raising questions about how the trial will unfold.

In May, just as the Senate was preparing to receive the impeachment complaint from the House of Representatives, Duterte ally Senator Ronald "Bato" dela Rosa turned up in the chamber after being absent from public view since November, and cast the decisive vote to install Alan Peter Cayetano as Senate president.

Dela Rosa then holed up in the Senate before slipping away early on 14 May, hours after chaos and gunfire erupted in the parliament building. His whereabouts are unknown.

Cayetano was the running mate of Duterte's father in the 2016 election. Rodrigo Duterte is in The Hague awaiting trial on murder charges linked to his "war on drugs". Dela Rosa, who faces similar charges from the ICC, was national police chief during much of the crackdown, in which thousands of suspects were killed. Both men have denied wrongdoing.

About a month later, senators aligned with a rival bloc secured enough support to elect Senator Sherwin Gatchalian as Senate president.

While the infighting highlighted alliances within the upper chamber, analysts said that should not be taken as a firm indicator of how senators will vote in the trial.

"The impeachment process creates a different set of incentives and constitutional responsibilities than leadership contests or coalition politics," Tapia said.

The outcome of the trial could also influence who emerges as the standard-bearer of the Marcos camp in 2028. Marcos is constitutionally barred from seeking a second term.