The Senate impeachment court opens the trial of Vice President Sara Duterte on Monday, 6 July, setting in motion a constitutional process that will test not only the evidence against her but also the political resolve of the senator-judges who will decide her fate.

The proceedings are expected to push through even if only the minimum quorum of 13 senators is present, amid speculation that some Duterte allies may skip the opening session.

What begins today is expected to unfold over months, with prosecutors and defense lawyers battling over allegations involving confidential funds, unexplained wealth, alleged threats against President Ferdinand Marcos Jr., First Lady Liza Araneta-Marcos, and former House Speaker Martin Romualdez, as well as other accusations contained in the Articles of Impeachment. The proceedings will open with House prosecutors and Duterte’s lawyers delivering their opening statements before the court moves into what is expected to be the longest phase of the trial — the presentation of witnesses and documentary evidence. No witnesses are expected to testify on the first day.

The Senate’s Pretrial Order has already laid down the roadmap for the proceedings, identifying the issues to be resolved, the evidence to be offered, the witnesses to testify, and the facts already stipulated by both parties.

Among the prosecution’s expected witnesses is the individual publicly known as “Mary Grace Piattos,” while one of the most closely watched pieces of evidence remains the sealed “BIR box” containing the income tax records of Duterte, her husband, Manases Carpio, and their businesses.

The tax records have remained under seal after senator-judges deferred action during the pretrial stage because of legal concerns surrounding taxpayer confidentiality.

The box

Former Supreme Court associate justice Adolfo Azcuna (see related story) has suggested that the Senate, acting in its legislative capacity, could legally open the records before endorsing them to the impeachment court, although the proposal has yet to be acted upon.

Legal observers also expect procedural battles over documentary evidence and witness testimony before the impeachment court fully confronts the merits of the complaint.

Senate Secretary Renato Bantug Jr., clerk of the impeachment court, said the trial could proceed as long as at least 13 senators are present, saying a full attendance is not required to establish a quorum.

Under the Constitution, conviction requires the votes of at least two-thirds of all senators, or 16 of the 24 members.

A guilty verdict would remove Duterte from office and could permanently disqualify her from holding any public office. Failure to obtain the required votes would result in her acquittal.

Whatever the outcome, the impeachment verdict will not preclude separate criminal or civil cases should investigators later find sufficient grounds to file them.

A major question that may ultimately be resolved by the Supreme Court is whether the 16 votes needed for conviction could be reduced because of the absence of Sen. Ronald dela Rosa and the detention of Sen. Jinggoy Estrada on separate legal cases.

House prosecution panel adviser and Surigao del Norte Rep. Robert Ace Barbers, meanwhile, said the proceedings could be completed earlier than expected if both camps agree that the evidence already presented is sufficient, eliminating the need to present all witnesses and documentary evidence.

Senate President Sherwin Gatchalian has likewise urged both sides to streamline their presentations to shorten the trial.

“A full court isn’t necessary. Even in our previous proceedings, it wasn’t required,” Bantug said in Filipino in a radio interview.

“There will be a roll call anyway. Once we’ve established that there’s a quorum, the impeachment court can proceed with its agenda for the day,” he added.

Gatchalian’s allies comprise the 13-member majority bloc.

The trial opens under intense public scrutiny, with civil society groups urging senator-judges to set aside political loyalties and decide the case solely on the evidence presented in court.

‘Guilty’

On Sunday, members of Tindig Pilipinas carried symbolic copies of the four Articles of Impeachment from the House of Representatives to several government offices to underscore what they described as the constitutional duty of public accountability.

“Whatever political considerations our senators may have, they will be judged by the Filipino people,” Tindig Pilipinas co-convenor Kiko Aquino Dee said.

Dee said he believes the evidence already available supports conviction but acknowledged that the final judgment rests with the Senate.

“I believe conviction is the straightforward outcome,” he said.

He cited the impeachment article involving Duterte’s alleged grave threats against the President, the First Lady and Romualdez.

“On the grave threats charge alone, the evidence speaks for itself. The whole country has already seen the video,” Dee said.

Duterte’s legal team reiterated that it would not attempt to derail the proceedings through procedural delays.

‘Persecution’

Defense spokesperson Michael Poa said the vice president’s lawyers would continue to raise legal and constitutional issues they consider necessary to protect her rights but “will not employ dilatory tactics” to stall the trial.

Duterte has consistently maintained that the impeachment case is politically motivated, forming part of a broader effort to derail her political future ahead of the 2028 presidential election.

Her allies have repeatedly accused the Marcos administration of weaponizing government institutions to weaken its strongest potential rival, an allegation Malacañang has consistently denied.

The impeachment proceedings have also been linked to the deepening rift between the Marcos and Duterte camps following the arrest and transfer of her father, former President Rodrigo Duterte, to the International Criminal Court.

The Vice President has publicly portrayed the move as political persecution and has vowed to continue defending her family’s name despite the legal and political battles confronting her.