As the noise and colour of a two-month election campaign subsides, a game of thrones between the two most powerful families in the Philippines resumes.

President Ferdinand “Bongbong” Marcos Jr, and his Vice-President, Sara Duterte, are embroiled in a bitter feud, and a battle for power.

As allies they won a landslide victory in the last presidential election in 2022.

But as their relationship has fractured – he accusing her of threatening to assassinate him, she accusing him of incompetence and saying she dreamed of decapitating him – this mid-term election has become a critical barometer of the strength of these two political dynasties.

And the results were not great news for the Marcos camp. Typically incumbent presidents in the Philippines get most of their picks for the senate elected in the mid-term election. The power of presidential patronage is a significant advantage, at least it has been in the past.

But not this time.

Only six of the 12 winning senators are from the Marcos alliance, and of those one, Camille Villar, is only half in his camp, as she also accepted endorsement from Sara Duterte.

Four of the senators are in the Duterte camp, including the president’s sister Imee Marcos. Two were in the top three vote-winners, ahead of any Marcos candidate.

For a sitting president, this is a poor result.

Senators are elected on a simple, nationwide vote, which is a good indication of national opinion. The result could weaken the authority of the Marcos administration in the last three years of his term, and it casts doubt on the plan to incapacitate Sara Duterte by impeaching her.

The Marcos-Duterte relationship has been deteriorating almost since the start of their administration three years ago. But it was only this year that it ruptured completely.

The decision by the president’s allies in Congress to start impeaching the vice-president was the first irreparable breach.

Then in March President Marcos sent Sara’s father, former president Rodrigo Duterte, to the International Criminal Court to face charges of crimes against humanity over his brutal war on drugs. The police have also now filed criminal charges against her.

The gloves were off. Impeachment would result in Sara Duterte being barred from public office, ending her ambition to replace President Marcos at the next election.

Right now she is the frontrunner, and few doubt that, if successful, she would use the power of the presidency to seek vengeance against the Marcos’s.

But impeachment requires two thirds of the 24-seat senate to vote for it, which is why this mid-term election mattered so much to both camps.

Politics in the Philippines is a family business. Once a family achieves political power, it holds onto it, and passes it around the various generations.

While there are around 200 influential families, the Dutertes and Marcoses sit at the top of the pyramid.

The Marcoses have been in politics for 80 years. The current president’s father ruled from 1965 to 1986, imposing martial law, and plundering billions of dollars from the national purse.

Bongbong Marcos’ mother, Imelda, who at the age of 95 cast her vote in this election from a wheelchair, is an even more notorious figure, and not just for her shoe collection.

His sister Imee has been re-elected to the senate, thanks to her decision to defect to the Duterte camp.

His eldest son Sandro is a congressman, and his cousin Martin Romualdez is speaker of the lower house and a likely presidential candidate in 2028 – probably the reason why Bongbong Marcos was so keen to drive through the impeachment of Sara Duterte.

In the president’s home province of Ilocos Norte, his wife’s cousin has been elected governor, his nephew elected vice-governor, and two other cousins elected as city councillors. Up there, Marcoses always win.

Much the same is true of the Dutertes in their stronghold in Davao at the other end of the country.

Even from his prison cell in The Hague, former President Duterte ran for mayor of Davao, and won easily, even though all voters got to see of him was a life-size cardboard cutout.

His absence will not matter though, because the previous mayor was his son Sebastian, who now takes over the vice-mayor’s job. Dutertes have been mayors of Davao for 34 out of the last 37 years.

The problem confronting both camps is that the senators also typically come from big political families, or are celebrities in their own right – many candidates come from a media or showbiz background.

They have interests and ambitions of their own. Even if officially allied with one camp or the other, there is no guarantee they will stay loyal, especially on the issue of impeachment.

“Senators in the Philippines are very sensitive to national public opinion, because they imagine themselves as vice presidents or presidents in-waiting,” says Cleve Arguelles, a political scientist who runs WR Numero Research, which monitors public opinion.

“So, they are always trying to read the public mind, and side with public opinion because of their future political ambitions.”

In recent months public sentiment has not been on the president’s side.

Bongbong Marcos has never been a good public speaker, and his stage appearances in the campaign did little to lift his flagging popularity.

His management of the economy, which is struggling, gets low marks in opinion polls, and his decision to detain former President Duterte and send him to the International Criminal Court is being portrayed by the Duterte family as a national betrayal.

At an impromptu rally in Tondo, a low-income neighbourhood in Manila’s port area, Sara Duterte played an emotionally-charged video of the moment her father was taken into custody at Manila’s international airport and put on a private jet to The Hague. She portrayed this as unforgivable treatment of a still popular former president.

“They didn’t just kidnap my dad, they stole him from us,” she told the cheering crowd.

Also on stage was President Marcos’s elder sister Imee, who disagreed with the extradition and jumped ship to the Duterte camp – though most observers view this as a cynical move to capitalise on Duterte popular support, so she could lift her own flagging campaign to retain her senate seat.

It worked. From polling low through much of the campaign, Imee Marcos managed to scrape into the “magic twelve”, as they call the winning senators.

What happens now is difficult to predict, but the Marcos camp certainly faces an uphill battle to get Sara Duterte impeached.

Of the 24 senators, only a handful are automatically loyal to the president. The rest will have to be persuaded to go along with it, , and that won’t be easy.

This election has shown that the Dutertes still have very strong public support in some areas, and some in the Marcos election alliance are already on record as saying they oppose impeaching the vice-president. The same goes for the 12 senators who were not up for election this year.

One bright spot for the president could be the surprise election of senators Bam Aquino and Francis Pangilinan, both from the liberal wing of politics.

Few polls had predicted their wins, which suggest a public desire for politicians outside the Marcos-Duterte feud.

Neither is a friend of the Marcos clan – liberals were the main opposition to the Marcos-Duterte team in the 2022 election.

But they were strongly opposed to the strongman style of former President Duterte, and may fear his pugnacious daughter becoming president in 2028. That may be enough to get them to vote for impeachment.

The impeachment trial is expected to start in July. The Dutertes can be expected to continue chipping away at the president’s battered authority in public, and both camps will be lobbying furiously behind the scenes to get senators onto their side.

No president or vice-president has ever been successfully impeached in the Philippines. Nor have any president and vice president ever fallen out so badly.

It is going to be a turbulent year.