MANILA, Philippines — The Philippine Senate, acting as an impeachment court, opened the trial of Vice President Sara Duterte on Monday in a politically volatile event that will unfold with the backdrop of her bitter political feud with President Ferdinand Marcos Jr.

More than 6,000 police officers, including anti-riot squads, were deployed to secure the Senate, where about 400 anti-Duterte demonstrators converged, chanting “convict Sara now.” Duterte did not appear but was represented by her lawyers at the start of the trial, which will run for 92 days, according to a pretrial plan seen by The Associated Press.

If convicted of the charges, which include amassing unexplained wealth and publicly threatening to have Marcos assassinated, Duterte may be permanently disqualified from holding public office. She denies the charges.

A conviction would be a lethal blow to her announced plan to seek the presidency in mid-2028, when Marcos ends his six-year term. They were running mates in the 2022 elections in a whirlwind alliance that combined the vote-getting power of two of the country’s most formidable political dynasties, but the union rapidly fell apart.

The vice president is the daughter of former President Rodrigo Duterte, Marcos’ predecessor. He was arrested last year on orders of the International Criminal Court and flown to The Hague, where he remains detained and was scheduled to face trial over alleged crimes against humanity on Nov. 30.

The charges stem from the ex-president’s brutal anti-drugs crackdowns that left thousands of mostly poor suspects dead, alarming Western governments and human rights groups. Rodrigo Duterte has denied authorizing extrajudicial killings but repeatedly threatened suspects with death while in office.

The vice president has blamed Marcos for her 81-year-old father’s arrest and handover to the ICC.

Marcos and the Dutertes have contrasting geopolitical leanings. Marcos has expanded defense engagements with the United States, his country’s treaty ally, as his administration stood up to China’s increasingly aggressive actions in the disputed South China Sea.

Rodrigo Duterte had nurtured cozy ties with Chinese President Xi Jinping and Russian leader Vladimir Putin while threatening to sever ties with Washington. The vice president has come under fire for not condemning China’s assaults, including with the use of powerful water cannons, against Filipino forces and fishermen in the disputed waters.

Last month, the House of Representatives, which is dominated by Marcos’ allies, voted overwhelmingly to impeach the vice president over alleged unexplained wealth, misuse of confidential state funds and a public threat to have the president, his wife and a former House speaker and ally assassinated if she herself were killed due to their political disputes.

She has generally denied the charges but has refused to publicly answer the allegations in detail ahead of the impeachment trial. Her supporters have accused Marcos and his key aides of politically persecuting the vice president and her senatorial allies to ensure her impeachment.

Two-thirds of the 24-member Senate, or 16 votes, are needed to convict the vice president.

Sen. Jinggoy Estrada, who belongs to a Senate bloc backing the Duterte family, was arrested and detained last month on a nonbailable charge of plunder in connection with a flood-control project bribery scandal. Estrada denies any wrongdoing.

Another pro-Duterte senator, Rodante Marcoleta, was arrested Monday over a nonbailable charge of plunder, or largescale graft, for receiving huge campaign donations and failing to declare the funds in his assets declaration. Marcoleta has denied committing any irregularity.

A third senator, Ronald dela Rosa, has gone into hiding after the ICC issued a warrant for his arrest as a co-perpetrator in the Duterte-era killings. Dela Rosa served as Rodrigo Duterte’s national police chief, who first enforced the then-president’s deadly crackdown against illegal drugs.

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Joeal Calupitan in Manila, Philippines, contributed to this report.