The arrest of Senator Antonio Trillanes is the latest round in his sparring with Duterte, whom he accuses of hiding wealth and being responsible for alleged executions of thousands of suspected criminals and drug dealers, which Duterte denies.

Trillanes has backed several complaints to the International Criminal Court (ICC) seeking the president’s indictment for crimes against humanity and has protected people willing to testify against Duterte.

“This is a debacle and a defeat of democracy,” Trillanes, a former navy officer, who accompanied arresting officers into a vehicle and was taken to a police station to be photographed and fingerprinted before posting bail, told reporters.

“We expect other forms of harassment in the days to come,” he said, adding that he expected the worst.

Presidential spokesman Harry Roque said it was time for Trillanes to stop grandstanding.

“The court has spoken,” he said in a statement. “Let us stop the drama by press conference and allow the legal process to take its course.”

Trillanes, a household name in the Philippines for his efforts to bring down the president, has stolen the political limelight in the three weeks since Duterte voided an amnesty given him by predecessor Benigno Aquino, citing flaws in the procedure, including a missing application form.

He had been holed up in his office under the Senate’s protection since Duterte’s order for the police and army to arrest him, although they were reluctant to do so.

Duterte later agreed a court warrant was necessary, following an outcry from opponents and legal experts who called it authoritarian and unconstitutional.

The revival of the charges against the senator was “the latest in the relentless campaign to silence those who dared to challenge the president’s murderous drug war,” New York-based Human Rights Watch said.

“Trillanes’ arrest today sends a chilling effect among other critics of the Duterte administration,” said Carlos Conde, a researcher at the rights group’s Asia office.

Trillanes received clemency after involvement in a failed 2003 coup and a mutiny four years later, both aimed at overthrowing then-President Gloria Macapagal Arroyo, an ally of Duterte who is now lower house speaker.

On Tuesday, a poll showed Duterte suffered the biggest ratings slump of his presidency in the third quarter, as public unease grows over rising inflation and the cost of staple foodgrain rice.

Duterte’s critics have accused him of trying to distract the public and prioritizing a settling of scores rather than tackling issues such as inflation, accusations his office rejects.