Former Senate President Franklin Drilon defended the installation of Sherwin Gatchalian as acting Senate president, saying the newly formed majority acted within constitutional bounds after acknowledging it lacked the votes needed to elect a permanent leader.

In a radio interview, Drilon explained that while the 12 senators present during the 3 June session had enough members to constitute a quorum and declare leadership positions vacant, the Constitution requires an absolute majority of 13 votes to elect a Senate president.

“You can remove because only 12 are needed, but you cannot elect a Senate president because 13 are needed,” Drilon said.

According to Drilon, the majority bloc was left with only 12 active members following the detention of Jinggoy Estrada on a non-bailable plunder charge and the continued absence of Ronald dela Rosa, who is facing an international arrest warrant.

Given the circumstances, Drilon said the senators properly relied on the chamber's rules of succession. The bloc elected Gatchalian as Senate president pro tempore, allowing him to assume the role of acting Senate president once the top post became vacant.

“You cannot elect a permanent president of the Senate if you do not have the vote of 13,” Drilon said. “That's why Sen. Gatchalian assumed as acting Senate president, because he was elected as Senate president pro tempore, and according to our rules, when the presidency of the Senate becomes vacant, the Senate president pro tempore assumes the position.”

Drilon said the move was necessary to allow the Senate to continue performing its functions, including preparations for the impeachment trial of Vice President Sara Duterte.

However, he acknowledged that the legality of the leadership change remains disputed. Former Senate President Alan Peter Cayetano, whose allies boycotted the session, has described the move as an “illegal coup” and maintains that he remains the legitimate Senate leader because 13 senators were not present to remove him.

Drilon said the issue will ultimately have to be settled by the courts.

“Even if I say that it is in order, ultimately, the Supreme Court is the one that will decide,” he said.

Still, he argued that the Senate could not remain paralyzed by continued boycotts that prevented it from conducting official business.

Drilon said the leadership shake-up “needed to happen” to allow the chamber to move forward with its work and continue addressing matters of national importance.