EXPLAINER: How Sherwin Gatchalian Became the Acting Senate President

(SPOT.ph) The Philippine Senate has been making headlines everywhere: from a gunfire scare to leadership turnovers. At the center of the latest hullabaloo are two competing claims: Alan Peter Cayetano insists he is still Senate President, while the former minority senators are rallying behind Sherwin Gatchalian who they've installed as acting Senate President. Confusing? Definitely. To cut through the noise, let’s break down what happened, why it happened, and why everyone is still fighting about it.

The Senate underwent a major shake-up after the minority bloc gained enough numbers to form a new majority on June 3. In that session, the 12 senators present moved to declare the elected Senate posts vacant to allow the Senate's business to proceed.

As we now know, Gatchalian has replaced Loren Legarda as Senate President Pro Tempore, placing him in a position to act as Senate President.

All of this came after two days of stalled Senate sessions. Numerous pieces of legislation were left on the line that even President Ferdinand “Bongbong” Marcos Jr. called on the senators to “get back to work.”

“I’m afraid all these events that we have been witnessing has thrown the whole Senate into disarray. It has discredited the leadership, and it has stopped the essential business of legislation and government,” Marcos said on June 3.

With the tables turning, Cayetano held on to his claim that he's Senate President—despite his thinning numbers on the Senate floor. He pointed to the Senate rules on succession, wherein the Senate Pro Tempore can only act as Senate President if the latter has resigned, died, or is in absolute incapacity. 

“I am still the legal, moral Senate president,” Cayetano said, insisting that the proceedings that brought Gatchalian to his now post constituted an “illegal coup d’etat that includes ​trampling on our Constitution.”

Can Cayetano still challenge the Senate shake-up while claiming to uphold his “duty to the Filipino people and to the Philippine Constitution”?

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The mess can be traced back to May 26, when the then-minority bloc walked out of the plenary session after clashing with the majority over a proposal to allow online Senate voting.

Cayteno claimed that the the same May 26 session had been adjourned with all 24 senators counted, meaning the Senate should resume on June 1 with the usual 13-senator quorum. If you’re wondering what a quorum is, it’s basically the required number of senators who need to be present before the Senate can officially conduct business. It requires a majority, or more than half, of all senators.

Normally, you'd need 13 senators to make a quorum in a 24-member Senate, as Cayetano had mentioned. However, the then-minority bloc argued that the quorum had changed to 12 because two senators cannot be compelled to attend. There’s Senator Jinggoy Estrada, who had been arrested over a plunder case involving alleged flood-control anomalies, and Senator Ronald “Bato” Dela Rosa, who had been absent from the chamber since May 11.

Senators from the then-minority bloc also cited the 1949 Supreme Court case Avelino vs. Cuenco, in which the court upheld the validity of a previous Senate session attended by only 12 senators. That is now the precedent being used to defend the June 3 session as valid. 

“Labing-dalawa kami, 10 sila. Ano ‘yung majority? This is not without legal basis at saka precedent, ano? Dahil ‘yung Avelino vs. Cuenco ay maliwanag,” Ping Lacson said in an interview on 24 Oras. “Dalawampu’t-dalawa kami ngayon dahil nga ‘yung dalawa indisposed at sinasabi doon outside the power of the Senate at hindi maco-compel ‘yung kanilang attendance.”

In more direct terms, if certain members are completely out of reach and the Senate cannot compel their attendance, they may be excluded from the count that is used to determine quorum.

According to Gatchalian, the Senate was compelled to convene on June 3 as Cayetano had failed to preside over the scheduled resumption of sessions on June 1 and 2, not to mention the absence of the majority bloc for two consecutive sessions following Estrada's arrest. Only the minority bloc showed up in the Senate session hall.

The effects of this Senate mess are now causing bottlenecks. Because of the Senate’s two-day impasse, House of Representatives Speaker Faustino “Bojie” Dy III said more than 160 measures have been transmitted to the Senate, only to be left on hold. Some of the key measures include the Magna Carta of Barangay Health Workers and the Anti-Hospital Detention Bill.

The move prompted the then-minority bloc to call for Cayetano’s resignation.

“What happened today was a clear abandonment of responsibility, a dereliction of duty, and a blatant disregard of the rules that govern this institution, because the Senate cannot be made to stop working simply because its presiding officer refuses to lead.” 

The deadlock broke when Senator Francis "Chiz" Escudero appeared in plenary, allowing the then-minority bloc to reach 12 senators—enough to reach a quorum.

According to Escudero, the Senate’s two-day impasse had become “unacceptable” as Congress is still in session.

“I am not taking sides. I am taking a stand for the Senate. My allegiance is not to any faction, personality, group or alliance. This is not about loyalty, betrayal, or choosing one group over the other—this is about duty,” Escudero said.

Also read: Chiz Escudero Is Ousted as Senate President. How Did We Get Here?

So are these changes to Senate leadership an "illegal coup" as Cayetano put it? According to the Malacañang Palace, the answer is no as the move was “anchored on existing jurisprudence and established parliamentary practice.”

Malacañang also recognized Gatchalian as the new acting Senate President, as per Palace Press Officer Claire Castro during a press conference on June 3: “Kinikilala ng Palasyo ang liderato ni Acting Senate President Sherwin Gatchalian.”

Several legal and political experts agreed. Former Far Eastern University Institute of Law Atty. Melancio “Mel” Sta. Maria pointed to Article VI, Section 16 of the Constitution which says an election for the position of Senate President requires a majority of all its members (24 senators), while all other elections require only a majority of the quorum. 

"All other elections" here include the post for Senate President Pro Tempore.

“‘Yung absolute majority of 13 applies to the election of a Senate President... Bukod doon, wala nang nakalagay... 24 minus two is 22, eleven is half, therefore 12 is the quorum,” Sta. Maria said.

University of the Philippines College of Law Associate Dean Atty. Paolo Emmanuel Tamase offered a similar explanation, saying Estrada is currently in the custody of the Judicial Branch, which means the Senate cannot interrupt his legal proceedings.

“Naturally, ‘yung kasama lang sa quorum ay ‘yung pwedeng papuntahin... Hindi pa natin nakikita ‘yung explanation ng minorya, pero mayroon kasi tayong at least dalawang members... pero hindi natin mahila,” Tamase explained.

The Integrated Bar of the Philippines (IBP) also weighed in, stating that the session where Gatchalian was named the new acting Senate President is lawful and valid follwing the Avelino doctrine. "Because a quorum of 12 Senators was constituted," he said. "All acts, resolutions and decisions made by the Senate during its session of June 3, 2026 are presumed to be official acts of the Philippine Senate."

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