September 23, 2026

Introduction

This is Working Draft's audio overview of the Impeachment Trial of Vice President Sara Duterte for September 23, 2026. This is a working reference, not an official Senate record. The court changed how it will calculate the votes required for conviction.

The ruling

The impeachment court granted Senator Erwin Tulfo's appeal by 13 votes to one, with six senator-judges not participating. It replaced its July 6 interpretation that conviction always required 16 votes. The chair said the constitutional two-thirds fraction will be applied to members legally and factually capable of participating when the eventual conviction vote takes place.

How the arithmetic works

First, the court must decide on competent and sufficient evidence whether any member is unable to participate. Possible grounds include legal restraint, unknown whereabouts while sought by authorities, medical incapacity, or being beyond the Senate's coercive process. The remaining capable members form the denominator. Two-thirds of that number is then rounded up to the next whole vote. For example, if 20 members counted, two-thirds would be 13 and one-third, requiring 14 votes. Twenty was an illustration, not a finding about the future vote.

The parties' arguments

For the prosecution, Representative Chel Diokno accepted the two-thirds fraction but argued that senators unable to do the court's work should not automatically count. He noted that a smaller denominator changes both sides of the arithmetic: with 20 members, 14 votes would convict and seven would block conviction. Defense counsel Michael Wesley Poa argued that all 24 occupied seats remain Senate membership, requiring 16 votes even when a senator does not participate. He warned that changing the rule during trial could unsettle the respondent's expectations.

Questions from senator-judges

Senator Bam Aquino pressed both sides on Supreme Court review. Diokno said review would be premature before a verdict made the threshold decisive; Poa said a midtrial change could itself be challenged. Senator Panfilo Lacson pointed out that in the Corona trial, two-thirds of 23 still rounded up to 16. Senator Pia Cayetano questioned whether the impeachment court could redefine who counts among all Senate members.

A separate procedural vote

Before the threshold ruling, Senator Alan Peter Cayetano appealed the chair's decision to proceed with that vote. The chair announced 13 affirmative votes, six negative votes and one abstention, and declared Cayetano's procedural appeal lost. That 13-six-one tally did not decide the conviction formula. Tulfo's threshold appeal received its own, later 13-to-one vote.

What remains open

The court has not decided which individual senators, if any, will be excluded when conviction is eventually considered. The precise number of votes needed therefore remains open. After the ruling, defense counsel Sheila Sison reserved the respondent's participation and available legal remedies. The chair said he would apply the court's decision.

Next sitting

No witness testified on September 23. The day's work was oral argument, questions and voting. The chair checked subpoenas for next week's witnesses, then adjourned the trial until Monday, September 28, at 10 a.m.

Closing

Each substantive point in this overview links to the reviewed transcript and the official Senate video. This has been the September 23, 2026 audio overview.