Human rights advocate and public interest lawyer, Atty. Antonio Audie Bucoy said Sen. Francis "Kiko" Pangilinan is the most qualified choice to serve as presiding officer of Vice President Sara Duterte's impeachment trial, citing his legal background, experience and reputation for impartiality.

Speaking in an interview on DZRH, Bucoy said the presiding officer wields significant authority over the conduct of an impeachment trial, making legal competence and neutrality essential.

"The presiding officer has broad powers," Bucoy said. "He orders the issuance of writs, summonses and subpoenas. He regulates the courtroom and rules on procedural questions, including whether evidence is competent, material and relevant."

Under the Senate impeachment rules, the presiding officer also decides procedural matters, enforces time limits and serves as the channel through which senator-judges may ask questions to witnesses.

Unlike regular court proceedings, senators are not allowed to directly question witnesses. Instead, they submit written questions to the presiding officer, who determines whether they are proper before asking them in open court.

"In other words, the presiding officer can filter the questions," Bucoy said.

Although rulings made by the presiding officer may be overturned by a vote of the Senate, Bucoy said the position remains crucial because it guides the overall flow of the proceedings.

"He is the one steering the entire process," he said.

Bucoy argued that Pangilinan is a stronger candidate than other names being floated because of his legal training and previous experience as a senator-judge during the impeachment trial of former Chief Justice Renato Corona.

"He studied law at the University of the Philippines College of Law," Bucoy said. "He has a clear advocacy for clean governance, and throughout his years in the Senate, he has not been tainted by corruption scandals."

He added that impartiality is just as important as legal expertise.

"The most important thing is impartiality," Bucoy said. "You should not only be impartial, you must also appear impartial."

Bucoy contrasted Pangilinan with Senate President Francis "Chiz" Escudero, whose possible role as presiding officer has drawn criticism from some sectors because of corruption allegations previously raised against him and statements he made criticizing the impeachment process.

Bucoy said those issues could create public perception problems regarding neutrality, although he clarified that any pending complaints against Escudero have no legal bearing on his authority to preside over the impeachment trial.

"They have nothing to do with the impeachment proceedings," Bucoy said.

The lawyer also noted that the Senate's amended impeachment rules now allow senators to elect a presiding officer instead of automatically assigning the role to the Senate president.

"They can nominate and they can choose," Bucoy said, adding that the amendment appears intended to give senators greater flexibility in selecting someone with the appropriate legal background.

He said only a few incumbent senators possess both legal training and experience relevant to presiding over an impeachment proceeding, describing the role as highly technical.

"Being a presiding officer is technical," Bucoy said. "You need legal training."

The Senate is expected to convene as an impeachment court ahead of the start of Duterte's trial, with senators expected to determine who will preside over the proceedings under the chamber's revised impeachment rules.