Vice President Sara Duterte’s defense on Wednesday warned the Senate impeachment court that reopening its 6 July ruling on the conviction threshold could make other rulings issued during the trial vulnerable to challenge.

Defense counsel Michael Poa said the court had already ruled on the first day of trial that 16 votes were needed to convict Duterte. No senator-judge objected to or sought reconsideration of the ruling at the time, he said.

More than two months later, the court is reconsidering the threshold after questions arose over whether absent or nonparticipating senator-judges should remain part of the denominator.

“Nothing in the rules suggests that the ruling of the presiding officer may be challenged indefinitely or modified arbitrarily,” Poa said.

“If you reopen this and vote on it, then every ruling of the presiding officer becomes fair game,” he added.

The defense said changing the threshold after the parties had already presented evidence could also raise due process concerns, particularly because both sides had conducted the trial under the assumption that 16 votes would be required for conviction.

“Parties must be able to rely on the rulings of the presiding officer,” he said, warning that changing the threshold in the middle of trial could raise due process concerns.

‘No supervening event’

Poa further argued that the rules governing impeachment proceedings do not set a specific period for seeking reconsideration of the presiding officer’s ruling. But he pointed to other procedural rules that impose deadlines for challenging decisions, including the Senate rules and the Rules of Court.

Under the Senate rules, a senator generally has two session days to seek reconsideration of a measure, while the Rules of Court generally provide a 15-day period for motions for reconsideration.

Even if the 6 July ruling were treated as an interlocutory order that could be modified during trial, Poa said the defense saw no basis for doing so.

“There was no sufficient ground, wala pong supervening event,” he said.

The senator-judges who are now unable to participate in the proceedings, he added, were already unable to participate when Escudero issued the 6 July ruling, except for Sen. Loren Legarda.

“So one thing is clear. Nothing in the rules suggests that the ruling of the presiding officer may be challenged indefinitely,” Poa said.

The defense maintained that even on the merits, the threshold remains 16. Article XI, Section 3(6) of the Constitution requires the concurrence of “two-thirds of all the Members of the Senate” to convict an impeached official. 

Poa said the phrase refers to the full 24-member Senate, not only members present or participating. “Absence, Your Honors, does not create a vacancy. Non-participation does not create a vacancy,” he said.

Cayetano warns of ‘mistrial’

Senator-judge Alan Peter Cayetano, who raised the threshold issue during the proceedings, said the question should have been settled before the trial or brought to the Supreme Court because he considered it jurisdictional.

“Timing is essential,” Cayetano said. He warned that changing the denominator — and therefore changing the number of votes needed to convict or acquit — while the trial is already underway could expose the proceedings to a “mistrial."

Cayetano then named four senators who had missed the trial fully or partially: Jinggoy Estrada, Rodante Marcoleta, Ronald “Bato” dela Rosa and Loren Legarda.

“It’s not an accident na panay na sa opposition yung wala na nandito,” Cayetano said.

“There is realpolitik happening here,” he added.

He said that if the threshold question remains unresolved, it should be brought before the Supreme Court rather than repeatedly changed as the composition of participating senator-judges shifts.

“If there is a question on the threshold, the question [should] be brought before the Supreme Court,” he said.