The split has intensified the legal jeopardy Rodrigo Duterte faces from the horrors of his so-called drug war. About 30,000 people are estimated to have been killed during his tenure, many of them victims of summary executions.

He was long seen as being essentially immune to prosecution in the Philippines. But the Marcos administration is reopening cases from that time and has let the International Criminal Court, which is investigating Duterte, send officials to the Philippines to conduct inquiries. This has led some to believe that Marcos would allow the court to arrest his predecessor.

“They made a 180-degree turn,” said Harry Roque, a former spokesperson for Rodrigo Duterte. “Their goal is to really send Duterte to The Hague.”

There is also speculation that Sara Duterte, who is likely to run for president once Marcos’ term ends in 2028, could face impeachment proceedings before then. Polls show that she is still the frontrunner for the next election, though her numbers have slid dramatically because of the conflict with Marcos.

The infighting has kept the government from dealing with many of the structural problems, like unemployment and poverty, that plague this country of roughly 110 million. The midterm elections in May, when voters will pick half of the powerful Senate, are now considered a proxy battle between the two clans.

Marcos “has to destroy the Dutertes”, said Ronald Llamas, a political analyst and former adviser to president Benigno Aquino III, who died in 2021. If the Dutertes do well in the midterms, he said, they will get back at the Marcoses “with a vengeance”.

The Philippines elects its president and vice president separately, and it is not unusual to find them on opposite sides of an issue. But never has the state been so consumed by such a feud.

Martin Romualdez, the speaker of the House of Representatives and a cousin of the president, is overseeing a months-long inquiry into the Duterte administration, including the extrajudicial killings and the ramifications of the pro-China policy. Rodrigo Duterte was invited to testify on Tuesday but declined.

In the past few weeks, the public has been told by a retired police colonel that Duterte paid cash for drug killings (he denies this); that the elected mayor of the municipality of Bamban, who was photographed with Duterte, could be a Chinese spy; and that the brother of a former adviser to Duterte has links to a criminal network that runs scam compounds.

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Marcos – widely known by his childhood nickname, Bongbong – first met Sara Duterte in October 2021, when his sister, the senator, brokered a meeting. He formally joined the presidential race a few months later, even though Duterte was the clear frontrunner and was facing pressure from her father to run.

In November 2021, Duterte stunned the country by announcing that she would run alongside Marcos on a platform of unity. People who know her say she was keen to show she was independent of her father.

The candidates called themselves the “Uniteam”. But at Marcos’ headquarters, Duterte’s allies were only allowed to access the “Sara floor”, according to Roque. Duterte ran her campaign from her own headquarters, he said.

“It was either you’re a Team Duterte or Team Marcos,” said Roque, who was in hiding because he faces an arrest warrant on contempt charges for failing to attend a hearing in Congress.

After the election, Duterte’s camp asked Marcos to allot half of the cabinet to her allies – a request that shocked the president, according to a person close to Marcos. One of the first public signs of friction was when Duterte was denied the defence portfolio, something she had expressly coveted.

The turning point in the relationship came in May 2023, when the House unexpectedly removed Gloria Macapagal Arroyo, a former president, as senior deputy speaker.

Arroyo is a mentor of Duterte, and the move infuriated the vice president. Some observers said that Arroyo had been trying to oust Romualdez, so he moved first. In a social media post, Duterte called Romualdez a “shameless monster” and later denounced “political toxicity.”

“That case with Martin triggered everything,” said Salvador Panelo, Rodrigo Duterte’s lawyer, referring to Romualdez. “If Bongbong intervened, the alliance might still be alive today.”

Around that time, the first lady, Liza Araneta, went public with her disdain for Sara Duterte.

Then came scrutiny of Duterte’s use of discretionary funds that are typically not subject to strict government audit. Last October, the House of Representatives announced that it was blocking the discretionary funds requested in the 2024 budgets of two agencies headed by Duterte.

In January, the Dutertes held an expletive-laden “prayer rally” in the city of Davao, their home base. Mayor Sebastian Duterte, a son of Rodrigo Duterte, said Marcos should think of the fates that befell the Romanovs and Benito Mussolini. (They were assassinated.)

“And think of what happened to you in 1986, and maybe you’ll reconsider the direction that you are taking,” he added, referring to the year Marcos’ family fled to Hawaii after enormous public protests ousted his father.

Few believe that the relationship between the two dynasties can be repaired. Last month, after Sara Duterte said she was “never friends” with Marcos, the president said he was a “little dismayed”.

“I always thought that we were,” Marcos told reporters. “But maybe I was deceived.”

This article originally appeared in The New York Times.

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