Even constitutionalists have conflicting opinions on the number of votes needed for the Senate impeachment court to convict Vice President Sara Duterte, underscoring the likelihood the Supreme Court may have to settle the debate.

Retired Associate Justice Adolfo Azcuna holds that the 16 votes constituting three-fourths of the Senate is a rigid number based on the Constitution’s number of members of the Senate, which is 24, “whether or not they are present or able to participate actively, as long as they remain members of the Senate, they should be counted in computing the two-thirds.”

“So right now, the number for me is still 16 because the senators who are unable to participate remain members of the Senate,” Azcuna said.

“The Constitution does not exclude members who are unable to participate in counting the two-thirds. There’s a reason for that: to make sure the process isn’t easily obtained. So to protect the tenure of our highest officials, the Constitution is very strict that the two-thirds vote must be based on the entire Senate membership,” he said.

However, if Senator Ronald “Bato” dela Rosa is adjudged to be a fugitive, he may be considered to have resigned under a constructive resignation, and the denominator becomes 23, putting the threshold at 15, Azcuna noted.

“Being a fugitive entails running away from the legal system. And if one runs away from the legal system, he relinquishes all membership in that system,” he held.

“If it becomes 24 minus 1 — 23 — two-thirds of that is 15. Because in computing, you ignore fractions. So if you exclude Senator dela Rosa for being a fugitive and considered resigned, no longer a senator, then you have15 to convict,” Azcuna said.

If dela Rosa suddenly shows up, cooperates with the authorities and is jailed, he ceases to be a fugitive.

“If he submits to the legal system, even if he’s detained, he remains a senator. So in my computation, he would still be included, and the denominator stays at 24,” Azcuna added.

How many can vote?

Former Supreme Court Senior Associate Justice Antonio Carpio, however, has a different view, saying the number of senators required to convict VP Duterte could fall below 16, depending on how many lawmakers can vote.

Carpio said the voting threshold is not fixed and will depend on the total number of senators present when the Senate sits as an impeachment court. The trial is scheduled to begin on 6 July.

Carpio explained that the actual number needed may change if some senators are unable to participate.

He pointed to the case of Sen. Jinggoy Estrada, who is currently detained and under suspension by the Sandiganbayan.

Carpio noted that despite his situation, Estrada remains a senator, but his participation in the vote may be affected.

On the other hand, dela Rosa is in hiding due to an arrest warrant issued by the International Criminal Court (ICC) over the previous administration’s war on drugs.

Carpio said the threshold could further decrease if other senators become unable to vote due to their detention or other legal circumstances.

He said the impeachment process could also be prolonged if the Senate court grants a motion to dismiss filed by Duterte’s camp.

Carpio said that in that case, the prosecutors are expected to elevate the matter to the Supreme Court, potentially extending the proceedings.