Amici Curiae: Impeach Court To Tap Legal Experts On Voting Threshold
The proceedings on Sept. 16 will be suspended to make way for a full-day hearing with the amici curiae or special resource persons. Oral arguments from the prosecution and the defense panels will take place on Sept. 23.

Constitutional experts will be tapped by the Senate impeachment court – as amici curiae or friends of the court – to resolve a possible deadlock over the number of votes required to convict or acquit Vice President Sara Duterte as four senators remain absent for various reasons.
Presiding officer Francis Escudero made the announcement on Tuesday, Sept. 8, after Sen. Erwin Tulfo formally appealed his ruling on the first day of the trial in July, setting the conviction threshold at 16 votes based on the full 24-member Senate.
“Given the sensitive and serious nature of this issue and topic, as discussed earlier with counsels for the parties and the senator-judges, we will be enlisting the opinion and assistance of amici curiae, or friends of the court so to speak, in order to give their opinion with respect to this issue,” Escudero said.
The proceedings on Sept. 16 will be suspended to make way for a full-day hearing with the amici curiae or special resource persons. Oral arguments from the prosecution and the defense panels will take place on Sept. 23.
Escudero said a vote to sustain or overturn his ruling would be held immediately after the oral arguments on the same day.
Sens. Jinggoy Estrada and Rodante Marcoleta are detained for plunder, while Sen. Ronald dela Rosa is in hiding and Sen. Loren Legarda is on an extended medical leave abroad.
“We would just like to put on record that whatever participation that the respondent and the defense would have on any oral argument or on any debate or proceeding relating to the matter taken up by honorable Sen. Erwin Tulfo in his motion, which the presiding officer had taken to be an appeal of his ruling on July 6th, would be only out of abundant caution, and without prejudice to any remedy that the respondent through her defense team would avail,” defense lead counsel Sheila Sison said.
In his manifestation, Tulfo questioned whether the constitutional phrasing “all members” strictly means 24, regardless of the absence of four lawmakers who are beyond the Senate’s coercive jurisdiction.
Tulfo pointed out that the chamber relies on the 1949 Supreme Court ruling Avelino versus Cuenco in determining a legislative quorum, which calculates the majority based only on members physically capable of attending.
“If we insist that the voting base is fixed at 24, regardless of the evidence presented, regardless of the vote of the senators who are able to listen to the testimonies, the absence of those senators, whether we like it or not, will result in an acquittal by default,” Tulfo argued.
The mention of the Avelino doctrine prompted Sen. Pia Cayetano to take the podium and recall the June 3 “rump session” by the 12-member majority of now Senate President Sherwin Gatchalian to oust her brother Alan Peter Cayetano as Senate president after the latter’s session boycotts.
Pia spoke for her brother, the now Minority Leader Alan Peter, who was absent at Tuesday’s proceedings.
“It was said that this body has consistently relied on the Avelino v Cuenco. That’s not accurate. These 12 members used the Avelino v Cuenco for their own purposes to declare there was a quorum. The now-minority does not agree to that. Let’s not make it appear it’s the rule of the Senate,” Pia said.
Impeachment court spokesman Reginald Tongol confirmed Escudero’s plan to get help from retired Supreme Court justices and constitutionalists.
He noted that sitting justices cannot participate as chances are high that the threshold issue would eventually be elevated to the High Court. Tongol said at least three experts would be invited, but stressed nothing is final yet.
When asked if it was possible for the amici curiae to advise the Senate to simply let the Supreme Court decide on the threshold issue, Tongol acknowledged it is possible.
“Of course, the opinions of the amicus curiae will be taken with great consideration by the senator-judges,” Tongol said.
Aside from the threshold, Tongol noted that the legal experts would also have to settle the distinct legal statuses of the absent senators – specifically whether detained lawmakers suspended under the anti-plunder law should still be counted as part of the chamber.
Sen. Francis Pangilinan said the issue is “separation of the powers between the judiciary and the legislative branch and impeachment court,” as he called on the Senate to also respect the Sandiganbayan’s jurisdiction over Estrada and Marcoleta.
Sen. Bam Aquino said the issue “is not really a question of guilt or innocence; it is a matter of threshold.”
Sen. Joel VIllanueva said the constitutional provision is clear that the vote to convict is 16 of all 24 members.
“This is very clear to me: ‘No person shall be convicted without the concurrence of two-thirds of all the members of the Senate.’ I thought that is non-debatable. But now that there is an appeal, which I totally understand,” Villanueva said.
Sen. Robin Padilla, a vocal Duterte supporter, said the 1987 Constitution is clear about 16 of 24 votes to convict. – With Marc Jayson Cayabyab, Bella Cariaso














