Senator Ping Lacson on Sunday said he had proposed allowing detained senators to physically attend the impeachment trial of Vice President Sara Duterte under police escort to ensure full participation in the proceedings.

The proposal came after Ombudsman Boying Remulla disclosed that around nine to 10 senators are under investigation over their alleged involvement in the flood control scam.

While Remulla did not identify the lawmakers involved, Lacson warned that any arrests or suspensions could significantly reduce the number of senator-judges and complicate the impeachment trial set to begin on 6 July.

Article XI, Section 3(6) of the Constitution requires the concurrence of two-thirds of all Senate members, or 16 votes, to convict an impeached official.

“One solution to really maximize participation or voting [turnout] is for us to file a motion for leave of court to allow them to attend the impeachment trial, even if they are under the escort of the BJMP (Bureau of Jail Management and Penology) or their custodian,” Lacson said in Filipino during a radio interview.

“Otherwise, it's going to be a crisis. There will be no impeachment because there are not enough senator-judges left,” he added.

Lacson said such a motion could be filed before the Sandiganbayan unless the Ombudsman issues preventive suspension orders against the senators concerned.

Aside from Senator Jinggoy Estrada, Lacson said Senators Francis Escudero and Joel Villanueva were among those allegedly facing possible arrest in connection with the flood control controversy.

He reiterated that the constitutional requirement for conviction remains fixed at 16 votes.

“I can only speak for myself, and I think my colleagues in the majority bloc also share the same view — that we should stick first and foremost to the Constitution. If it states 16, or two-thirds of 24, then it is 16. You cannot reduce that,” Lacson said.

The senator also disclosed that some members of Acting Senate President Win Gatchalian’s bloc disagreed with that position, although he did not identify them.

The issue stems from the leadership change in the Senate on 3 June, which allies of Senator Alan Cayetano have criticized as unconstitutional for allegedly lacking the required majority vote.

Cayetano has repeatedly argued that reducing the quorum requirement could set a precedent for lowering the number of votes needed for conviction in an impeachment trial. Gatchalian, however, has maintained that the 16-vote threshold remains unchanged regardless of attendance.

Lacson said reports indicating that Escudero may preside over the impeachment trial remain subject to the Senate’s collective decision. He added that Senator Kiko Pangilinan is also being considered for the role.

The pre-trial conference for Duterte’s impeachment case is scheduled on 18 June, with both the prosecution and defense required to submit their pre-trial briefs by 15 June.

Duterte faces allegations of betrayal of public trust, culpable violation of the Constitution, graft and corruption, and other high crimes. She has denied wrongdoing and described the impeachment proceedings as politically motivated.