Manila (AFP) -
The son of late Philippine dictator Ferdinand Marcos was set to address hundreds of thousands of supporters Saturday on the final day of presidential election campaigning, as polls show him heading towards a landslide win.
Victory in Monday's election would cap a decades-long effort to rehabilitate the Marcos legacy after the patriarch was deposed and the disgraced clan chased into US exile.
But the prospect of Ferdinand Marcos Jr moving back into the presidential palace has alarmed rights activists, church leaders and political analysts who fear he could rule 'without constraint'.
Ten candidates are vying to succeed President Rodrigo Duterte in the landmark elections seen by many as a make-or-break moment for Philippine democracy.
The Marcoses' remarkable return from pariahs to the peak of political power has been fuelled by public anger over corruption and poverty that persisted under governments that followed the dictatorship.
Polls indicate Marcos Jr will win more than half the votes, which would make him the first presidential candidate in the post-Marcos era to secure an absolute majority.
Analysts warn such an outcome would lead to weaker democratic checks and balances, more corruption and a fresh attempt to overhaul the 1987 constitution -- which could include scrapping the one-term limit for presidents.
'If he wins really big that could give him the kind of confidence and momentum to more radically alter the Philippines political system,' analyst Richard Heydarian told AFP.
Previous administrations, including Duterte's, have tried to amend the constitution drafted after the elder Marcos was ousted in 1986.
They lacked sufficient support in Congress to push through changes.
But the latest poll by Pulse Asia Research showed Marcos Jr on 56 percent -- 33 percentage points ahead of his nearest rival Leni Robredo, who narrowly beat him in the 2016 vice-presidential race.
Such a winning margin would give Marcos Jr the power to 'govern the way Duterte wanted to', one long-time observer of Philippine politics told AFP.
'That is without constraint,' he said.
Robredo, 57, has warned supporters that the 'future of the country' is at stake.
Her recent poll bump has raised hopes among progressive supporters that their volunteer-driven campaign could yet deliver an upset.
But pollster Ana Maria Tabunda of Pulse Asia Research said there was little chance of that.
'Our error margin is only plus or minus two percentage points -- given the large gap it's not going to be affecting the results,' Tabunda told AFP.
- 'Another six years of hell' -
Hundreds of thousands of supporters were expected to turn out Saturday in Manila for the final rallies of Marcos Jr and Robredo ahead of the election. Monday's winner only needs to get more votes than anyone else.
Still smarting from his 2016 loss, Marcos Jr has run a tightly controlled campaign, skipping televised debates with rivals and largely shunning media interviews to avoid own goals before election day.
He has instead posted folksy videos on YouTube that seek to present him and his wealthy family as regular Filipinos, and taken softball questions from celebrity interviewers.
A massive and well-funded social media misinformation campaign targeting a mostly young electorate with no memory of his father's violent and corrupt rule has also sought to rewrite the family's history.
Marcos Jr's popularity has been further enhanced by a formidable alliance with vice-presidential front runner and first daughter Sara Duterte, and the backing of several rival political dynasties.
Days ahead of the election, rights defenders and many Catholic priests made a final push to stop Marcos Jr returning to the Malacanang Palace, where he grew up.
'It will be another six years of hell,' warned political satirist and activist Mae Paner, 58, who was part of a popular uprising that ended the elder Marcos's regime and has been campaigning for Robredo.
Hundreds of Catholic priests publicly endorsed Robredo and her running mate Francis Pangilinan, telling their flocks the election was a 'battle for the soul' of the nation.
But Robredo faces an 'uphill battle', said Cleve Arguelles, an assistant lecturer in political science at De La Salle University in Manila.
After enduring six years of attacks from the elder Duterte, Robredo has seen her popularity hammered by a relentless and vicious online smear campaign.
Heydarian said Robredo's late decision to enter the race had cost valuable time, while 'unnecessary infighting' among rival candidates had benefited Marcos Jr.
'They are handing this on a silver platter to the princeling of Philippine politics, Bongbong Marcos,' he said, using Marcos Jr's nickname.