MANILA, Philippines — Pasig City Mayor Vico Sotto, if he will be allowed to run for president in 2028, could emerge as the only serious challenger to Vice President Sara Duterte, a survey conducted by Tangere showed. Tangere found that three in four Filipinos (75 percent) favor Senator Tito Sotto’s proposal to amend the Constitution and reduce the age requirement for presidential candidates from 40 to 35. The strongest support came from younger and middle-aged voters between 18 and 48 years old. In a standard scenario where only current eligible contenders are considered, Duterte dominates the field with 44 percent voter preference—up nine points from the previous quarter. Her strength is concentrated in Central Visayas, Davao Region, and Northern Mindanao. Former vice president and Naga City mayor Leni Robredo trails far behind at 20 percent, buoyed mainly by voters in Metro Manila and the Bicol Region. But the picture changes dramatically once Vico Sotto enters the equation. The Tangere survey’s alternative scenario shows the Pasig mayor drawing 34 percent support nationwide, statistically tying with Duterte. His backing is strongest in Metro Manila, Southern and Central Luzon, Northern Luzon, and Western Visayas. The data suggest that Sotto pulls voters directly from both Duterte and Robredo’s bases: one in five Duterte supporters and nearly half of Robredo’s backers switch to him when given the option. The survey further highlights the potential kingmaker role of Robredo. Nearly nine out of 10 of her supporters said they would back whoever she endorses if she does not run. With more than half of her voters already leaning toward Sotto in the alternative scenario, her endorsement could tip the balance in his favor against Duterte. The non-commissioned survey was conducted August 27 to 30 via Tangere’s mobile-based platform, sampling 1,400 respondents nationwide with a margin of error of ±2.57 percent at a 95percent confidence level. Tangere is a member of the Marketing and Opinion Research Society of the Philippines, the European Society for Opinion and Market Research, and the Philippine Association of National Advertisers.