Raul Dancel

In booting Vice-President Leni Robredo out of his Cabinet, President Rodrigo Duterte is reining in dissent to ensure his policies and plans, including his controversial anti-crime drive, will go on, whatever happens to him.

But he also may have flagged a rallying figure for a growing, but still fragmented, opposition.

No longer tethered to Mr Duterte, Ms Robredo is promising to "oppose policies with a louder voice".

Ms Robredo, who belongs to the opposition Liberal Party of former president Benigno Aquino, resigned as housing secretary on Monday after she was instructed to stay away from Cabinet meetings.

She believes the move is part of a plot to "steal the vice-presidency" from her and hand it to former senator Ferdinand Marcos Jr, Mr Duterte's preferred surrogate.

Mr Marcos, 59, who lost by a narrow margin to Ms Robredo, 52, in the May elections, has since been moving to unseat her via a recount of votes.

Ms Robredo has taken part in rallies slamming Mr Duterte for allowing the burial of Mr Marcos' father, the dictator who ruled the Philippines for more than 20 years amid widescale human rights atrocities and plunder, at Manila's national heroes' cemetery.

She has also criticised the killings that have blighted Mr Duterte's violent war on drugs, opposed his plan to reinstate the death penalty, and called him out for joking about ogling her legs during his meetings with her.

Mr Duterte had wanted merely to "discipline" the vice-president and to get everyone to toe the line, his spokesman Ernesto Abella said.

But that has not stopped speculation that the President wanted Ms Robredo out, so that if anything unfortunate happens to him before his term ends, he can rely on someone like Mr Marcos to carry out his programmes.

"You have all the ingredients for a conspiracy theory at play," said Associate Professor Eduardo Araral of the Lee Kuan Yew School of Public Policy.

Questions about his health have hounded Mr Duterte, 71, ever since he decided to run for president. He has admitted to having a slipped disc from a motorcycle accident about 10 years ago. He also has Barrett's oesophagus, a digestive ailment that may lead to cancer, and Buerger's disease, a swelling of the arteries and veins in the arms and legs caused by years of smoking.

Mr Duterte lately has had bouts of migraine, which caused him to miss events at the Asean summit in Laos and Apec meeting in Peru. Two weeks ago, his aides had to deny rumours that he had collapsed.

The health scares have made it urgent for Mr Duterte to look for a backup he can trust. That would be Mr Marcos.

But that is also galvanising opposition to his rule, centred on Ms Robredo.

A spate of rallies attended by tens of thousands greeted his decision to allow a burial for the Marcos patriarch. Unseating Ms Robredo as vice-president may trigger protests as large as the 1986 People Power revolt, some analysts say.

But for Prof Araral, Ms Robredo lacks the gravitas to challenge the still hugely popular Mr Duterte.

"I think (Mr Duterte) will continue to enjoy widespread support from the population in the coming years as indicated by recent polls. He is widely seen to be decisive and authentic, the very reasons that he won with a wide margin," he said.

"The opposition would have to have a much more colourful language and character to be able to overshadow the President."