MELBOURNE, Australia — To his many critics, he is an uncouth braggart with a penchant for politically incorrect jokes and a populist dislike for Western allies, but when Filipinos go to the polls Monday, they are widely expected to elect Rodrigo Duterte as president and initiate a political shake-up with unpredictable consequences in the battle for regional influence.
Of the five candidates in the presidential election, only Grace Poe — a well-liked businesswoman, senator and philanthropist — appears to stand in the way of a candidate whom many have called the Filipino Donald Trump. A Pulse Asia survey has put the support of Mr. Duterte, the mayor of Davao City on the southern island of Mindanao, at about 35 percent, with Ms. Poe a distant second at 23 percent.
There is no runoff, so one-third of the vote may give Mr. Duterte six years in power in Manila.
The intricacies of the nation’s notoriously insular politics typically do not attract much international attention, but the next president will be on the front lines of the increasingly bitter battle of wills pitting China against the U.S. and virtually all of Beijing’s East Asian neighbors for control of some of the world’s strategic and heavily trafficked waterways.
It also could bring a sharp break from a period of relative stability under term-limited President Benigno Aquino, who has worked to improve ties with the U.S. military while presiding over an economy averaging growth over 6 percent a year since 2012. Under his stewardship, the Philippines jettisoned its image as the “sick man of Asia,” standing its ground against Chinese maritime expansionism, hammering out a peace deal of sorts in the long-troubled south and attracting record foreign investment.
The break would be both in style and substance, longtime watchers of the combative 71-year-old Mr. Duterte say.
Instead of campaigning on major issues, the front-runner has tried to capitalize on the Philippines’ notorious machismo culture, reeling off one-liners that have earned him comparisons to Mr. Trump, but with a vulgarity that would make even the presumptive Republican presidential nominee blush.
Mr. Duterte drew rebukes from the Australian and U.S. ambassadors with a jaw-dropping attempt at humor, commenting at a campaign rally last month on the gang rape of an Australian missionary before she was killed during a prison riot.
“What a pity they raped her. They all lined up. I was mad she was raped, but she was so beautiful. I thought the mayor should have been first,” he told laughing supporters in an exchange caught on tape.
The prison is in Davao City, where Mr. Duterte has served several terms as mayor or as deputy since 1988.
He has two mistresses and has promised they won’t cost the public purse too much because he puts them up in cheap housing.
But he has also effectively portrayed himself as a can-do champion of the poor who will take on the Manila elites and the small group of families that have long dominated the country’s politics. He pledges to move faster on reforms and — like Mr. Trump — sells his ability to get things accomplished without providing specifics.
“I will solve drugs, criminality and corruption in three to six months,” he told Al Jazeera in an interview last month. “I am the only remaining card left for the Filipinos to deal with the situation.”
Also like Mr. Trump, he paints himself as an outsider who delights in taking on the Manila establishment. His main rivals include the sitting vice president and two sitting senators. Mr. Aquino’s preferred successor, former Interior Minister Mar Roxas, is a longtime insider whose father was a senator and whose grandfather was president in the 1940s.
As for critics who say he should tone down his rhetoric and refine his abrasive style, Mr. Duterte retorted, “I would rather lose the election than lose my identity.”
Mr. Duterte’s halfhearted apologies for his more provocative remarks are often accepted by this overwhelmingly Catholic nation — even after he called Pope Francis the “son of a whore” last year for the inconveniences a papal visit had caused his city — with his tough-guy image winning over the largely impoverished masses.
“The slums are getting bigger, and the rich are getting richer. Statistics show 40 families own almost 80 percent of the wealth, and the poor are his constituency,” said Karl Wilson, an academic with the Manila-based Asian Center for Journalism.
“The point is, he’s hugely popular because he’s seen as a man who can bring in law and order. He loves being called ‘Dirty Harry,’ and he plays on that image. He cracks down hard on petty criminals and drug dealers particularly.”
Mr. Duterte’s claim to eradicate crime in six months points to his long record in the provincial Davao City in the country’s insurgency-prone south. Human rights groups say his methods have cost hundreds of innocent lives.
A key plank is a promise to double the salaries of police and the military immediately after taking office. Officials accused of using excessive force to fight crime and corruption, up to and including himself, will be pardoned by presidential decree, he said.
“He is quite proud of his achievement in Davao City, where some 2,000 criminals have been executed on the streets by vigilantes over the last few years,” Mr. Wilson said. “When asked what he would do if his son took drugs, he said, ‘I would kill him myself.’”
In addition to dealing with China’s increasingly aggressive push in the South China Sea, the next government must handle a proposed bill to create an autonomous region, to be known as Bangsamoro, reached under a peace deal signed with the Moro Islamic Liberation Front in 2014.
Any further delays threaten to reignite a conflict with a radical Islamist splinter group formed out of hard-line elements that is upset with the slow pace of reforms.
This is further complicated by overlapping communist, indigenous and Islamic insurgencies. Bandits in groups such as Abu Sayyaf, which has sworn allegiance to the Islamic State, are holding more than 20 foreigners hostage.
In late April, they beheaded a Canadian hostage, John Ridsdel, who was taken in Davao Nord, not far from Mr. Duterte’s home. His head was found in a gutter.
“The fact that the Philippine military and security forces are so incompetent and corrupt provides the perfect haven for hardened terrorists to hide out and train,” Mr. Wilson said.
The next president will face early pressure to deal with the South China Sea.
A decision on Filipino legal action brought against China’s territorial claims in the nearby Spratly Islands is due from the U.N. Permanent Court of Arbitration in late May or early June. Manila and its allies, led by the U.S., have spent months preparing for the decision.
Naval drills such as Exercise Balikatan 2016, a U.S. Pacific Command operation with the Philippines, Australia and regional observers, have put Manila at the center of what some analysts are calling one of the world’s hottest sovereignty disputes.
Mr. Duterte’s policy approach, however, seems more in line with his populist down-home attitude than the stuff of potentially deadly naval brinkmanship. He has said he will ride into the disputed territories on a personal watercraft and plant a Philippines flag on the Spratly Islands — even if he has to carry out the mission himself.
He also could represent a strain on the longtime relationship between Manila and Washington. Seizing on anti-American sentiment, Mr. Duterte bluntly told the U.S. and Australia — the country’s two biggest military aid donors — that they could leave if they were so outraged by his rape joke.
More broadly, Mr. Duterte vows to protect the Philippines’ territorial claims in the South China Sea but has also hinted that he is ready to talk directly with Beijing about joint development of the disputed areas.
As Mr. Duterte holds his lead in the polls, his rivals are taking a harder line against him.
Ms. Poe’s camp charged that Mr. Duterte stashed more than $4 million in hidden bank accounts — a sizable sum in the dirt-poor Philippines — and said he will carry on Mr. Aquino’s policies that have failed to bring widely shared prosperity to the country.
Some women are refusing sex unless their men drop their support for the Duterte camp.
“But if Grace Poe wins, it will be situation normal,” Mr. Wilson said.
Former legislator and political commentator Mong Palatino said Ms. Poe could snatch victory from Mr. Duterte by attracting votes from the remaining three candidates.
In March, the Supreme Court of the Philippines cleared Ms. Poe, 47, a popular senator and the adopted daughter of two movie stars, to run for president. She was earlier disqualified from the race because of doubts about her citizenship.
“About the chances of Grace Poe? Yes, she can still win,” Mr. Palatino said. “She has the solid backing of major parties, she remains popular among voters, she topped the Senate race in 2013, she survived the disqualification threat and other legal challenges to her candidacy, and some administration supporters are switching sides in order to stop Duterte from winning.”
A report by the Asia Foundation has found the race too close to call.
“With such a tightly contested race, it is bound to be a ‘last two minutes’ kind of game, with each candidate scrambling to make the winning shot,” said Maribel Buenaobra, the foundation’s deputy country representative.
She noted the comparisons of Mr. Duterte to Mr. Trump.
A video criticizing his remarks was shared thousands of times online, with Twitter critics tagging their tweets #RapeIsNotAJoke.
“Filipinos will troop to the polls and make a judgment. Will sense and decency prevail? Or will madness, braggadocio and false promises overtake our better judgment?” Ms. Buenaobra asked. “Heaven help us. We are whom we vote for.”