However, Vice President Duterte did not attend the opening session of the trial. Instead, her legal team said she opted to appear through counsel rather than being physically present in the proceedings.

“In accordance with the impeachment rules, karapatan naman po niya ‘yan that her appearance be made through counsel. So sa ngayon, masasabi natin hindi na siya mag-a-attend today. She’s here through counsel,” defense spokesperson Michael Poa told reporters.

The session, which began around 2:00 p.m., was presided over in its opening phase by Senate President Sherwin Gatchalian, who delivered an opening statement before calling for the election of the presiding officer of the impeachment court.

The selection of a presiding officer immediately became the first major point of debate among senator-judges.

Lawmakers argued over whether the Senate president should automatically preside over impeachment proceedings.

Senator Alan Peter Cayetano cited the 1987 Constitution, insisting that the Senate president should serve as presiding officer of the impeachment court.

However, Senator Kiko Pangilinan countered that the Constitution does not explicitly require the Senate president to preside over impeachment trials.

“The Constitution does not provide that the Senate President must preside in cases of impeachment trial,” Pangilinan said.

Following the debate, Escudero was elected presiding officer of the impeachment court after a 12–8 vote among senators.

Escudero noted during the proceedings that Vice President Duterte was not physically present at the opening session but was adequately represented by her legal team.

“The Vice President is not physically present but represented more than adequately by her counsels, who entered their appearance,” he said.

Escudero also said the conviction threshold is 16—"Without a tinge of doubt, 2/3 of the figure or not less than 16 members, is unquestionable compliance with the requisite number of votes mentioned in Section 21 of Article 7.”

House prosecution panel and defense team

The 11-member House prosecution panel was present in full during the first day of trial, formally entering their appearance before the impeachment court.

Meanwhile, members of the defense team for Duterte, led by Atty. Shiela Sison also submitted their entry of appearance on behalf of the Vice President.

Duterte was impeached by the House of Representatives on May 11, 2026, for a second time, making her the first Filipino official to be impeached twice by the lower chamber.

The articles of impeachment were subsequently transmitted to the Senate, which convened as an impeachment court after holding pre-trial conferences from June 18 to 25.

Duterte is facing impeachment allegations, including alleged misuse of confidential funds, unexplained wealth, bribery, and issuing death threats. She has denied all accusations.

Cayetano proposes attendance of detained senators in VP Duterte impeachment trial

Senator-Judge Alan Peter Cayetano proposed that the Senate impeachment court coordinate with the Sandiganbayan to allow detained senators Rodante Marcoleta and Jinggoy Estrada to attend the impeachment trial of Vice President Sara Duterte.

He said their presence is important to ensure full participation in evaluating evidence and maintaining the integrity of the proceedings, which he described as “sui generis.” Presiding Officer Senator Francis “Chiz” Escudero said the proposal will be discussed with the senator-judges and relevant parties for further consideration.

House Prosecution Sets Sequence of Impeachment Articles