MANILA — Senator Panfilo “Ping” Lacson on Friday invoked the 1949 Avelino v. Cuenco ruling as he criticized former Senate President Alan Peter Cayetano’s actions amid the ongoing leadership dispute in the Senate.

In a post on X, Lacson compared Cayetano’s approach to that of former Senate President Jose Avelino, who brought his leadership conflict with Mariano Cuenco before the Supreme Court.

“The only difference being – Avelino brought his case to the Supreme Court. Cayetano does not have Avelino’s decency and respect for the same rule of law,” Lacson said.

The Supreme Court ruling in Avelino v. Cuenco arose from a Senate controversy on Feb. 18, 1949, when Avelino and his allies were accused of attempting to block Senator Lorenzo Tañada from delivering a privilege speech containing allegations against him.

Avelino later banged the gavel and left the session hall, while the remaining 12 senators continued proceedings, recognized Cuenco as presiding officer, declared the Senate presidency vacant, and installed Cuenco as acting Senate President.

Last Wednesday, 12 senators composed of 11 members of the then-minority bloc and Senator Francis Escudero convened despite a boycott led by Cayetano and members of the former majority bloc.

The group elected Senator Sherwin Gatchalian as Senate President Pro Tempore and acting Senate President, citing the Supreme Court ruling in Avelino v. Cuenco as basis for the chamber’s quorum.

Cayetano, however, maintained that he remains Senate President. On Thursday, a day after the Senate adjourned sine die, he appeared with some allies in what they described as a Blue Ribbon Committee hearing.

Lacson also hit Cayetano for allegedly dragging his name into the proceedings, saying it was done “without an iota of evidence or even a tiny bit of basis or reason except to pull me into a corruption controversy.”

“He exposed his loathsome behavior by using overstretched innuendos. He is disgusting,” Lacson said.