MANILA, Philippines — It may be more difficult for Vice President Leni Robredo to defend her electoral win in the poll protest filed by former Sen. Ferdinand “Bongbong” Marcos Jr. with changes in the Presidential Electoral Tribunal’s composition, retired Senior Associate Justice Antonio Carpio said.

Carpio is one of the two justices who held that Marcos’ election protest should be junked after he failed to make out his case in his chosen three pilot provinces, but they were outvoted by 11 other justices.

The retired justice told ANC’s "Headstart" Thursday that for Robredo, it would be “more difficult,” noting that it would be one less vote for the vice president but he assured that the Supreme Court, sitting as PET, is aware of the significance of this case.

“I think the court will also consider the implications of all of these if you allow a protestant [to go] outside of the pilot provinces because that will prolong the election contest and that will change the rules,” Carpio explained.

President Rodrigo Duterte is also set to appoint three more justices, to replace Carpio and retired Chief Justice Lucas Bersamin. The president will also fill the associate justice seat of Chief Justice Diosdado Peralta.

He added that the House of Representatives Electoral Tribunal and the Senate Electoral Tribunal also follow the same set of rules: Consider the three pilot provinces in the case and decide on whether it will be dismissed or not.

“Now, if we allow other precincts to be considered, that will be a departure and we have to consider the ramifications of that,” the retired justice also said.

Carpio dissent

In his dissenting opinion, Carpio insisted that Rule 65 of the PET expressly states that “the number of pilot provinces must ‘not be more than three.’”

Marcos is asking the court to proceed with this third cause of action that is determining whether there is electoral fraud in three provinces in Mindanao.

EXPLAINER: What is PET Rule 65 and why are Robredo's lawyers bringing it up?

“The Tribunal will be violating its own Rules if it allows a revision and recount of ballots in other provinces in the Autonomous Region in Muslim Mindanao, beyond the maximum three provinces chosen by protestant,” he warned.

“The last thing that this Tribunal should do is to change its rules in midstream to accommodate a party who has failed to comply with what Rule 65 of the 2010 PET Rules expressly requires,” Carpio stressed.

Carpio said he is proud of the last vote he cast before retiring. He was joined in the dissent by Associate Justice Alfredo Benjamin Caguioa, who initially was the member-in-charge of the case.

READ: Carpio ends 'defining era' stint at SC

Change in member-in-charge no material effect

Reports quoting unnamed sources from the SC said that the poll protest has been raffled off to Associate Justice Marvic Leonen.

Carpio assured that a new member-in-charge of the case “would not be material,” unless the tribunal proceeds with the third cause of action.

“Initially it will have no effect because the first issue will be whether the court will allow three more provinces to be considered,” the retired justice said.

“If the court will allow 3 more provinces to be considered then that will be material for the ponente because the ponente will be in charge of revision and recount of the 3 more provinces,” he explained.

RELATED: Marcos seeks more time to photocopy poll recount documents

Leonen is one of the 11 justices that voted to allow Marcos and Robredo to comment on the release of the initial recount report and on the move to proceed with Marcos' third cause of action.

He later explained that his vote was for due process. “You do not want a court to condemn without hearing, no matter what the consequences are, you do not want to condemn,” he said.