MANILA, Philippines — Retired Supreme Court Associate Justice Adolfo Azcuna said an impeached official could not be convicted if only 15 of the Senate’s 24 members were available to participate, because the Constitution requires the concurrence of two-thirds of all senators for a conviction.
Azcuna made the statement during Wednesday’s hearing as amici curiae, or “friends of the court,” were questioned on the constitutional issues surrounding the impeachment trial of Vice President Sara Duterte.
In his interjection, Sen. Panfilo Lacson asked Azcuna to consider a hypothetical situation in which nine of the 24 senators became stranded abroad because of a prolonged war, leaving only 15 senators available to participate even though all 24 remained Senate members.
“Where will fairness to the Filipino people go in such a situation?” Lacson asked, stressing that he was not suggesting that the respondent was guilty but was raising a hypothetical question about how fairness could be ensured if only 15 senators were available and capable of participating.
Lacson said he believed the framers of the 1987 Constitution could not have anticipated the current circumstances, in which he said one senator-judge was in hiding, two were detained without bail and one was abroad.
“I agree with former Chief Justice Reynato Puno that we cannot be so rigid as to fix the voting threshold to 16, which is two-thirds of 24 senator-judges,” the senator said.
Azcuna, however, said that if only 15 senators remained available while the Senate still legally consisted of 24 members, “there can be no conviction” because the Constitution requires the concurrence of two-thirds of all Senate members.
He compared the situation to a Supreme Court case in which the justices fail to obtain the votes required to declare a law unconstitutional.
“In that case, under your rules, if you cannot get the 16, it’s an acquittal. A judgment of acquittal will be entered,” Azcuna said.
He clarified that such an acquittal would not necessarily mean that a majority of participating senators had voted to acquit the respondent.
Rather, it would result from the failure to obtain the constitutionally required 16 votes for conviction.
The Constitution provides that no impeached official may be convicted without the concurrence of two-thirds of “all the Members of the Senate.”
Senate Presiding Officer Francis “Chiz” Escudero has interpreted this as requiring 16 votes from the current 24-member chamber, a ruling challenged by Senator-Judge Erwin Tulfo.
Azcuna acknowledged that applying the 16-vote requirement under extraordinary circumstances could result in an impeachment case failing to produce a conviction.
He described this as the possible “price” of maintaining a supermajority requirement for conviction.
“But it’s a rare occasion, rare event which in that case is a price we pay for the internal check of a supermajority threshold that there are occasions when accountability through impeachment will fail,” Azcuna said.
He added that impeachment is not the only mechanism for accountability, citing criminal proceedings, forfeiture cases and elections.
Lacson, meanwhile, argued that circumstances involving senators being unavailable because they are in hiding, detained without bail or unable to return from abroad may demonstrate why the constitutional voting threshold could be subject to debate as circumstances change.
Retired Chief Justice Artemio Panganiban took a different view, saying the Senate should still be able to resolve an impeachment case with the senators who are present.
“Fairness can be rendered by two-thirds of those present. It’s not necessary that 16 should vote in favor, because it’s impossible to get 16,” Panganiban said.
He argued that denying the Senate the ability to act because of circumstances beyond its control could deprive the public of a resolution of the impeachment case.
“Our people still deserve to be given justice because the 15 present can still act and render justice, and be able to discipline whoever is to be disciplined,” Panganiban said.
Lacson later shifted the discussion to whether the Senate’s interpretation of the voting threshold could eventually be challenged before the Supreme Court.
He raised the issue in connection with a manifestation ad cautelam, or a filing made as a precaution, by defense counsel Michael Poa, suggesting that the impeachment court should consider the possibility that its eventual ruling could be subjected to judicial review.
Panganiban said a disagreement by the Supreme Court with the Senate’s interpretation would not, by itself, justify judicial intervention.
He pointed to the constitutional standard of grave abuse of discretion, asking whether the Senate had acted in a capricious, whimsical or arbitrary manner.
“If we cannot agree, how can you be faulted for debating in something that the Supreme Court may disagree?” Panganiban said.
The Constitution grants the judiciary the power to determine whether any branch or instrumentality of government has committed grave abuse of discretion amounting to lack or excess of jurisdiction.
The Supreme Court has reiterated in recent impeachment-related litigation that the Senate, as a co-equal constitutional body, generally operates within its own sphere, while its actions remain subject to judicial review for grave abuse of discretion.
In an April 2026 ruling involving a petition seeking to compel the Senate to convene as an impeachment court, the Supreme Court said the Senate’s exercise of its constitutional duties is beyond judicial control through mandamus, except in cases of grave abuse of discretion.
The High Court also said the Constitution gives the Senate discretion on when to begin an impeachment trial, subject to the requirement that it proceed within a reasonable time.
The continuing debate among the amici curiae therefore centers on how the constitutional requirement of two-thirds of all Senate members should operate when some senator-judges are unable to participate, and on the extent to which the Senate’s interpretation of that requirement may be reviewed by the courts.
