Retired Supreme Court Chief Justices Artemio Panganiban appears at the Senate impeachment court on Sept. 16, 2026 as amicus curiae, or "a friend of the court" to provide legal guidance on the constitutional voting threshold required for conviction. Maria Tan, ABS-CBN NewsMANILA — Retired Chief Justice Artemio Panganiban on Wednesday offered a path for the Senate impeachment court to resolve the contentious question of what is the least number of votes to secure a conviction in the impeachment trial of Vice President Sara Duterte, saying senator-judges should be guided by truth and fairness.
The Senate court has paused hearings for Duterte's trial to hear opinions from retired magistrates invited as amici curiae or "friends of the court" on the issue of conviction threshold.
One of the amici curiae invited by the Senate, Panganiban said the impeachment court, called sui generis or "of its own kind," should interpret the 1987 Constitution to reflect the "common sense" of the people guided by two fundamental standards: truth and fairness.
Senator-judges should themselves be present in the trial to see whether "witnesses are telling the truth, the whole truth, and nothing but the truth" and that fairness means "we hear before we condemn, that all sides are given the opportunity to explain," he said.
"In this connection, is it truthful and fair to allow senators to cast their votes despite being absent from the proceedings? Is it fair and truthful should the senators be allowed to vote, though they were there in hiding, abroad, legally detained, sick, hospitalized, or otherwise absent, and have not been able to access and examine the documents? Have not heard the testimonies, and have not observed the demeanor of the witnesses?" said Panganiban.
"Is it truthful and fair to the parties, to our country, and to our people, to allow those abroad? ... Can such duty be performed in the shadows of absence? Nor from legal impediments?"
Active participation and an independent evaluation of the evidence are "essential to discharge the Senate's and the senators' constitutional responsibility," he also said.
Davide: No impeach vote for senators charged with plunder, whereabouts unknown
The Senate court is confronted with the difficult task of resolving questions surrounding the conviction threshold following absences from several members of the 24-seat chamber.
Sen. Ronald dela Rosa has been in hiding for being wanted by the International Criminal Court for his role in former President Rodrigo Duterte's brutal drug war. Sen. Jinggoy Estrada and Sen. Rodante Marcoleta, meanwhile, are detained over plunder cases.
Participants in the impeachment trial had put forward differing views on how to interpret the constitutional provision guiding the Senate on the voting threshold to convict an impeached official.
Article XI Section 3(6) of the 1987 Constitution states: "The Senate shall have the sole power to try and decide all cases of impeachment. When sitting for that purpose, the Senators shall be on oath or affirmation... No person shall be convicted without the concurrence of two-thirds of all the Members of the Senate."
Some say the conviction threshold could be lowered because the constitution used the term "two-thirds" and that it is open to interpretation, but others argue that the number is fixed to 16 votes as the Senate is composed of 24 members.
Panganiban also stressed that whatever the decision of the Senate court on Duterte's case is "final and unappealable" and the "only way" that the Supreme Court can step in to review its ruling is if the chamber "commits grave abuse of discretion."
Prosecutors need to secure a guilty verdict on at least one article of impeachment to convict Duterte.
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