Retired Supreme Court Chief Justice Reynato Puno appears at the impeachment trial of Vice President Sara Duterte at the Senate of the Philippines in Pasay City on Wednesday, September 16, 2026. Maria Tan, ABS-CBN News
MANILA — Retired Chief Justice Reynato Puno on Wednesday said the Senate, sitting as an impeachment court, has the authority to interpret the constitutional provisions governing impeachment proceedings, including the rule on the number of votes needed to convict an impeached official.
Puno said this power stems from the Constitution’s express grant to the Senate of the “sole power to try and decide all cases involving impeachment.”
“My respectful submission, Your Honors, is that the Senate, as an Impeachment Court, possesses the power to interpret the meaning and nuances of that sentence,” Puno told the Senate impeachment court.
“The sole power to try and decide necessarily includes the lesser power to promulgate the rules that will govern the trial and decision of impeachment cases,” he added.
Puno was among the retired Supreme Court justices invited as amici curiae, or friends of the court, to assist the Senate in resolving the required number of votes needed to secure a conviction or acquittal in an impeachment trial.
Four senators are currently absent: Jinggoy Estrada and Rodante Marcoleta (detained on plunder charges), Ronald “Bato” dela Rosa (in hiding amid an ICC arrest warrant), and Loren Legarda (on medical leave).
'CONTEXTUAL, FUNCTIONAL SCHOOL OF THOUGHT'
Puno said the dispute over the two-thirds requirement illustrates why the constitutional provision should not be read in isolation from other provisions of the Constitution.
He said he does not subscribe to the textualist approach, which gives the provision a literal reading and could result in a fixed 16-vote threshold.
“With all due respect to others with contrary opinions, I do not subscribe to the first school of thought in interpreting Article 11, Section 3(6) of the Constitution. This school of thought espouses the textualist approach. Its proponents give a provision of the Constitution a literal reading, a reading that is isolated from other related provisions of the Constitution,” Puno said.
“I respectfully submit, however, that it is inappropriate to give Article 11, Section 3(6) a stand-alone literal reading,” he added.
Puno said such an interpretation would make the threshold immutable at 16 senators.
“If we give this kind of reading to Article 11, Section 3(6), the threshold of 16 Senators to convict will be fixed and immutable,” he said.
But Puno pointed out that the Constitution did not expressly say that 16 votes are required to convict.
“If that is the intent, Article 11, Section 3(6) should have simply stated that the number of votes to convict is 16, period. But Article 11, Section 3(6) did not say so. Instead, the language used a fraction,” Puno said.
“It says two-thirds of all members of the Senate. By using two-thirds, the number of votes to convict will have to move depending on certain factors,” Puno added.
He instead endorsed what he called the “contextual and functional school of thought,” which considers related constitutional provisions and the circumstances surrounding the exercise of the senators’ functions as impeachment judges.
“This interpretation is contextual because Article 11, Section 3(6) is interpreted not in isolation but in relation to other provisions in the Constitution in order to give life to its purpose,” he said.
“It is functional because it will give the Senators the flexibility to consider circumstances that will legally prevent a Senator from functioning as a member of the Senate,” he added.
Puno said this approach could allow the Senate to consider whether senators who are dead, resigned or expelled should still be included in determining the two-thirds threshold.
He also cited senators who are legally incapacitated, including those charged with plunder or placed under preventive suspension.
SENATE POWER IS BROAD BUT 'NOT ABSOLUTE'
Puno also disputed the argument that only the Supreme Court has the power to interpret the constitutional provision governing the impeachment court.
He said the judicial power exercised by the Senate in impeachment proceedings is distinct from the judicial power exercised by regular courts under the Constitution’s provisions on the Judiciary.
“The senator-judges are not like the judges of the regular courts of law, who are all under the supervision of the Supreme Court,” Puno said.
He noted that the Senate’s impeachment power is expressly provided under Article XI, or the Constitution’s provisions on accountability of public officers, rather than under Article VIII on the Judiciary.
Puno said the Constitution does not expressly give the Supreme Court the authority to review the Senate impeachment court’s rules, conduct of trial, evidence presented before it or its decision in an impeachment case.
“In general, Your Honors, all these questions are to be resolved alone by the Senate Impeachment Court, because it is the sole judge to try and decide impeachment cases,” he said.
Puno, however, said that the Senate’s authority is not absolute.
He said certain actions by the impeachment court may still be reviewed by the Supreme Court if they violate constitutional rights, including the right to due process and the right to be judged by an independent and impartial tribunal.
“The whole proceedings can be challenged as a patent nullity, including any judgment of conviction on the ground of denial of substantive and procedural due process,” he said.
'MEMBER' SENATORS
Puno said the word “member” in the constitutional provision should be understood in light of the function senators perform when they sit as impeachment judges.
“Thus the word member, member senators who will determine the guilt or innocence of a respondent in an impeachment case must be understood in the light of the function that they will discharge. More specifically, they will be acting as judges to try and decide impeachment cases,” he said.
“As judges, they must possess special qualifications. They must be independent, fair, and impartial,” he added.
Puno said personal observation of every witness is not an absolute requirement for a judge to decide a case, noting that judges and justices can rely on transcripts, affidavits and other records.
He cited trial judges who take over cases from predecessors and appellate and Supreme Court justices who decide cases based on the records rather than personally observing every witness.
Puno said the constitutional questions now before the impeachment court are issues of first impression.
“The deliberations of the 1935, 1973, and 1987 Constitutions did not discuss the issues now before us,” he said. “There is no correct or wrong decision on these issues. There is only a preferred decision.”
The Senate impeachment court on Wednesday is hearing the views of retired justices Puno, Artemio Panganiban, Adolfo Azcuna, and Hilario Davide Jr.
Davide: No impeach vote for senators charged with plunder, whereabouts unknown
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