MANILA — Senator Alan Peter Cayetano and eight other senators have asked the Supreme Court to invalidate the June 3 Senate session that resulted in the election of Senator Sherwin Gatchalian as Senate President Pro Tempore and led to changes in the chamber’s leadership.

In a report, it said that in an 86-page petition for certiorari filed on Tuesday, Cayetano, Senators Loren Legarda, Pia Cayetano, Jinggoy Estrada, Bong Go, Rodante Marcoleta, Imee Marcos, Robin Padilla, and Camille Villar sought the nullification of the proceedings held on June 3.

The petitioners also requested the high court to issue a status quo ante order restoring the conditions and positions that existed before the session took place.

Lawyer Jose Luis Montales, who served as Senate secretary under Cayetano, joined the petition.

The group challenged the validity of the quorum during the June 3 session and asked the court to void the approval of the motion declaring elective Senate positions vacant, the adoption of a resolution for sine die adjournment, and all actions stemming from what they described as a void session.

They likewise urged the Supreme Court to stop members of the Gatchalian bloc from exercising powers and functions associated with positions obtained during the questioned proceedings.

Among those covered by the request were retired Police Major General Alfredo Corpus, who was elected Senate Sergeant-at-Arms, Lawyer Renato Bantug, who was elected Senate secretary, and Senator Juan Miguel Zubiri, who was elected majority leader. The petition also questioned the designation of committee chairpersons following the leadership reorganization.

If the petition is granted, the group asked the Supreme Court to recognize Cayetano as Senate President, Legarda as Senate President Pro Tempore, Montales as Senate secretary, and to restore all Senate committee chairpersons who held their posts before June 3.

“Petitioners sought judicial intervention at the earliest practicable opportunity after the occurrence of the challenged acts. This prompt resort to the Honorable Court reflects neither haste nor speculation, but recognition of the substantial constitutional consequences that would inevitably follow if the controversy were left unresolved while the disputed actions continued to operate,” the petition stated.

The petitioners argued that the issues raised “could generate consequences beyond meaningful judicial correction.”

They added that the timing of the petition was important because the disputed quorum became the basis for decisions involving Senate leadership, committee structures, legislative inquiries, and impeachment proceedings.

“By seeking relief at the outset, petitioners have afforded the Honorable Court the opportunity to the constitutional matters involved before they are further overtaken by events,” they said.

In a social media post, Cayetano maintained that the petition was intended to protect institutions rather than advance leadership interests.

“Those who oppose it want to paint our motives in those simple terms—simple enough to twist, simple enough to confuse people about the real issues. Let me reiterate what we have said from the start: leadership positions are temporary stewardship. Leaders holding high government positions come and go. Political alliances change. Majorities rise and fall,” he said.

The petition was filed through the Supreme Court’s electronic filing system on June 16, a day before the Senate’s special session.

The senators also asked the high court to prevent the implementation of measures and resolutions approved during the June 3 session and to order respondents, including senators who assumed committee chairmanships under the Gatchalian bloc, to stop performing duties arising from the contested proceedings.

The petition specifically sought the nullification of the declaration of a quorum, the motion vacating elective positions, the election of Gatchalian as Senate President Pro Tempore and Acting Senate President, as well as the elections of Zubiri as majority leader, Bantug as Senate secretary, and Corpus as Senate Sergeant-at-Arms.

“Clearly, then, all the foregoing elections during the rump session on June 3, 2026 are void. Petitioner Senator Alan Cayetano thus remains Senate President; petitioner Senator Legarda remains Senate President Pro Tempore; and petitioner Atty. Montales remains Senate Secretary,” the petition read.

Aside from Cayetano and Legarda, the petitioners included Senators Pia Cayetano, Go, Marcoleta, Marcos, Padilla, Villar, and Estrada.

Not among the petitioners were Senators Mark Villar, Ronald “Bato” dela Rosa, and Joel Villanueva. Villanueva earlier said he would attend the Senate special session if directed by President Ferdinand Marcos Jr.

The filing comes amid an ongoing dispute over Senate leadership, with Cayetano’s bloc continuing to assert its legitimacy despite recognition of the Gatchalian-led group by Malacañang and the House of Representatives.

The leadership changes followed the June 3 session in which all committee chairmanships were declared vacant after the Senate recognized the existence of a quorum. The Gatchalian bloc cited a 2015 Senate precedent and the 1949 Supreme Court ruling in Avelino v. Cuenco in support of its position.