What the Senate coup means for Sara Duterte's impeachment trial

Sara impeachment as primary motivation

Thirteen senators voted for Cayetano, including Sotto as well as Duterte’s vocal allies like Sen. Ronald Dela Rosa, Sen. Bong Go, Sen. Robin Padilla, Sen. Rodante Marcoleta, and Sen. Imee Marcos. Sen. Camille Villar, Sen. Mark Villar, Sen. Loren Legarda, Sen. Pia Cayetano, Sen. Chiz Escudero, Sen. Jinggoy Estrada, and Sen. Joel Villanueva also supported the veteran lawmaker's election as Senate President. 

For political analysts, the main motivation behind the coup couldn't have been any clearer.

“The last time that something like this happened, the leadership changed. It had something to do with the impeachment also of the VP last year," Dennis Coronacion, political science professor at the University of Santo Tomas told PhilSTAR L!fe. He recalled the time when Sotto replaced Escudero as Senate President in September 2025, months after the Senate voted to return the Duterte complaint to the House the first time she was impeached, instead of pushing through with a full trial. "It seems that whenever there’s going to be a leadership change in the Senate, it’s centered on the impeachment of the vice president."

Michael Tiu Jr. of the UP College of Law also brought up the previous transmission, saying that no matter how senators framed their positions on Duterte's impeachment case before the media, "you do get the sense that some of them are not in favor of the impeachment or having a trial."

For his part, political scientist Cleve Arguelles pointed out that before the Senate leadership change, the then-majority, including Sotto, had been "making very public pronouncements that to them, as soon as the House reaches the required number to impeach the VP, they will do their constitutional duty to convene as an impeachment court forthwith." Arguelles called it the "axis" of the agreement between the majority and the minority.

Personal interests

While political analysts observed it was Duterte's impending trial that led to the coup, it was not the only factor at play. 

For Dr. Jean Franco, an associate professor at UP Diliman's Department of Political Science, the votes of the senators who sided with the now-majority "are really due to, obviously, personal interests."

Both Franco and Arguelles touched on the coup's possible link to the flood control scandal, following the Blue Ribbon Committee's recommendation to investigate some members of the Senate, including Escudero, Villanueva, and Estrada. "This is another axis na, of course, pagka-mayroong pagbabago sa Senate majority, that would also mean there would be a change in committee leaderships. We expect na 'yung report ng Blue Ribbon Committee, mawawala na 'yun. That will be buried already," Arguelles explained.

Tiu also pointed out Dela Rosa's ICC warrant in connection with his alleged involvement in extrajudicial killings under former president Rodrigo Duterte's war on drugs. Dela Rosa appeared in the Senate after a months-long absence on May 11, where he has been put under protective custody.

"Certainly, Bato risked going to the Senate and risked apprehension. He probably would not have succeeded in getting protection and being granted protective custody under a different leadership," Tiu told L!fe. "They’re also pursuing law enforcement officers who attempted to arrest him—that additional contempt citation we had seen at the Senate would not have been a guarantee if there was no leadership change."

Arguelles likewise noted that the ICC case may involve Go eventually since he was named as a co-perpetrator in the elder Duterte's drug war in an official document. "I think his vote was also an attempt to stay out of that situation," he said.

For Arguelles and Franco, the other senators who supported Cayetano's election have an axe to grind against the current administration. These include the Villar siblings, whose family is under investigation for alleged anomalies in their business, and Legarda, whose son Leandro Leviste has an ongoing feud with Executive Secretary Ralph Recto's family over alleged corruption and vote-buying as well as an ongoing issue with Energy Secretary Sharon Garin for alleged business violations linked to his solar company.

These must serve as a lesson that we have "too many dynasties" in the 24-member Senate, per Arguelles. "Napakaliit lang ng Senate, and now we see that many of the dynasties voted together, so I would point that out as a red flag. We have less entry points for those senators we want to, at least think as, independently minded. Nadadagdagan pa kasi ng familial interest so nagiging playground pa for dynasties."

Will VP's impeachment trial push through?

Duterte became the first official in the history of the Philippines to be impeached twice by the House of Representatives on Monday, May 11.

With Duterte allies emerging successful in their Senate coup, Arguelles said that the main worry now is that there might be no impeachment trial for the VP, as we have seen in the previous Senate presidency of Escudero. "They’ve done their best to really drag the process and delay any impeachment court at all so baka ganun din 'yung mangyari—they'll question some of the provisions again, what 'forthwith' means, how the House conducted its own proceedings," he said.

The political scientist stressed the importance of proceeding with the trial this time around. "They must show the evidence and explain their vote to the public why they think the VP is guilty or innocent of the charges against her," he pointed out. "If senators make it harder for a process of accountability to happen, to unfold in the Senate, Filipinos may take it outside the Senate."

Tiu noted that the Constitution commands that once the articles of impeachment are transmitted to the Senate, the trial must ensue forthwith. "There's no choice but to hold a trial now, whether there are going to be legal issues, or some delay in strategies that might be imposed," he said. "This also happened in the Estrada trial before. Some senators were opposed to having the trial, so they had no choice but to have a trial so they determined the procedure and there were certain votes in favor of the prosecution."

With the new Senate leadership, the political analysts see different possibilities in connection with Duterte's impeachment case,

The now-majority, who used to be the opposition, can now dictate the outcome as well as the process or procedure of the impeachment trial. "They will have to write the rules and that will definitely affect how the trial will play out," Franco told L!fe.

Coronacion added that the trial may take place to Duterte's advantage. "Pwede nilang gamitin 'yun to the advantage of the VP. Pwedeng palabasin nila during the trial proper na 'yung mga evidence presented at the House of Representatives are flawed para linisin 'yung pangalan ni VP," he said.

An acquittal or an outright dismissal of the articles of impeachment against the VP is also possibility. "Since pro-Duterte senators are in charge, they can easily dismiss the impeachment case, the articles of impeachment. Wala ng risk na maco-convict pa ang vice president," said Coronacion.

Tiu also raised the possibility of Duterte ending up with a conviction, "but they have the option not to impose the penalty of perpetual disqualification from office." This, he added, means that the vice president can run again and secure the presidency she's hoping for in the 2028 elections.