EXPLAINER: Power struggle rocks the Senate

A power struggle has erupted in the Senate, with Senators Alan Peter Cayetano and Sherwin Gatchalian each asserting their legitimacy to lead the chamber.

During a session on June 3, 2026, Gatchalian was elected Senate President Pro Tempore and acting Senate President after a quorum of 12 senators was established.

Cayetano rejected the move and insisted that he remains the Senate President. He also argued that electing a new Senate leader requires at least 13 votes from the chamber's 24 members, citing the 1987 Constitution and Senate rules.

Aside from installing Gatchalian, the June 3 session also reshuffled the leadership of several Senate committees, including the Blue Ribbon Committee, with Senator Erwin Tulfo replacing Senator Pia Cayetano as chair.

On June 4, Pia Cayetano proceeded with a committee hearing on alleged flood control anomalies even after Tulfo announced its postponement and said the inquiry would resume on June 8.

Pia Cayetano refused to acknowledge the Gatchalian-led June 3 session and called it “invalid.”

“I stand before you today to state clearly and unequivocally—that session was invalid. Wala po silang 13. Kahit Grade 1 marunong magbilang, kailangan ng 13. So hindi, wala ho silang authority gawin ‘yung mga ginawa nila,” she said.

(I stand before you today to state clearly and unequivocally—that session was invalid. They did not have 13 votes. Even a Grade 1 student knows how to count, and you need 13. So no, they don't have the authority to do what they did.)

The Pia Cayetano-led hearing was attended by allied senators and invited resource persons. However, no members of the Senate secretariat were present, and the proceedings were not livestreamed on the Senate's official platforms.

The Gatchalian bloc dismissed the hearing as "bogus."

“There are no official Senate hearings scheduled for this morning, and any so-called ‘hearing’ convened by Senators Alan Peter Cayetano, Pia Cayetano, (Robin) Padilla, and (Rodante) Marcoleta has no basis in the rules, calendar, or authority of the Senate,” the Gatchalian bloc said in a statement.

Before the hearing, Alan Cayetano accused the Gatchalian bloc of violating the Constitution and provoking a crisis through the actions taken during the June 3 session.

'Political disturbance'

Former law dean Atty. Mel Sta. Maria said Gatchalian's installation as acting Senate President was legal, arguing that his bloc followed proper procedures when it declared the Senate presidency vacant.

"There is an attempt to create a legal cloud of doubt as to the whole situation in the Senate when there is none. And therefore it is not even a constitutional crisis. Maybe it's not even a political crisis. Para sa akin (For me), it's pure and simple Senate disturbance," he said in a report by GMA News Feed.

“Because you are contending with the authorized authority and a group of people without authority,” Sta Maria said.

Sta. Maria said the June 4 hearing convened by the Cayetano bloc could only be regarded as an "illegal aggregation of people."

According to Sta. Maria, the Senate's calendar of activities can proceed despite the leadership dispute, as only a quorum is needed for the chamber to conduct business.

“Kamukha ngayon, on the basis of [the Supreme Court decision in] Avelino versus Cuenco, 12, makaka-do business… Pero nakakapanghinayang lang ang sinasayang ng publiko sa mga taong ‘yan na nag-a-absent,” he said.

(Similar now, on the basis of Avelino versus Cuenco, 12 [senators] can do business... But it’s just such a waste of public funds on those people who keep calling in absent.)

Impeachment

Sta. Maria said Vice President Sara Duterte's impeachment trial may not be affected by the leadership dispute, provided the Senate amends its rules to allow a senator other than the Senate President to preside over the proceedings.

He argued that the Constitution does not specifically mandate the Senate President to preside over impeachment trials, noting that such authority stems solely from Senate rules.

On June 5, the dispute reached the Supreme Court after a private school teacher filed a petition seeking clarification on the validity of the Senate quorum.

“Ina-ask ko lang po ‘yung Supreme Court kung valid ba yung quorum o hindi. Kasi nagkakagulo e, pati yung mga tao sa social media, pati yung ibang mga legal expert, nagkakagulo sila,” petitioner Barry Tayam said.

(I am just asking the Supreme Court whether the quorum was valid or not. Because there's a lot of confusion right now—even people on social media and other legal experts are arguing about it.)

Sta. Maria said that while Supreme Court intervention in a “highly political” Senate leadership dispute may not be ideal, a ruling on the petition could help clarify the issue.

In the meantime, Sta. Maria said the Senate should continue its work under Gatchalian's leadership.

“Ang very first presumption, the rule of regularity, that must be respected. And therefore the minority, tanggapin na lang muna nila and do the function of a minority,” he said.

(The very first presumption is the rule of regularity, and that must be respected. Therefore, the minority should accept it for now and simply perform the role and functions of the minority.)

“The most important thing is, who will be the one to be able to project that moral authority, to create a stabilized Senate for the time being?” he added. — VBL, GMA News