Within the margin of error, they were now statistically tied
A week before Peru's presidential runoff, what had appeared to be a decisive leftist advantage dissolved into statistical uncertainty. Pedro Castillo, the rural teacher turned political insurgent, and Keiko Fujimori, the conservative heir to a contested legacy, found themselves separated by a margin smaller than the poll's own error. The survey captured not merely a tightening race, but a country still searching for its direction — with rising protest votes and undecided citizens suggesting that neither candidate had yet earned the nation's trust.
- Castillo's ten-point lead collapsed in a single week, turning what looked like a foregone conclusion into a genuine dead heat with seven days left.
- Fujimori's surge — despite facing money laundering investigations — signals that fear of radical change may be pulling hesitant voters back toward the conservative camp.
- Protest votes and blank ballots are climbing, revealing a significant portion of the electorate that refuses to embrace either candidate as a legitimate choice.
- Undecided voters grew rather than shrank in the final stretch, meaning the race will be won or lost in the last-minute scramble to mobilize, persuade, and hold.
- With a margin of error swallowing the entire gap between the two candidates, Peru is heading into election day with no reliable forecast — only uncertainty.
One week before Peru's presidential runoff, the race had transformed. Pedro Castillo, the leftist teacher from Cajamarca leading Perú Libre, had held a commanding ten-point advantage just days earlier. Then a Sunday survey from the Instituto de Estudios Peruanos placed him at 40.3 percent — with Keiko Fujimori of Fuerza Popular at 38.3 percent. Within the poll's 2.8-point margin of error, the two were statistically tied.
The telephone survey, conducted across 24 departments and 387 districts with 1,227 respondents, captured a country in rapid motion. Fujimori, despite ongoing money laundering investigations, had closed the gap with striking momentum. Meanwhile, blank and null protest votes edged upward to 13 percent, and genuinely undecided voters rose to 6.3 percent — a sign that the electorate remained restless and unpersuaded.
The contest embodied a deep national divide. Castillo promised a constitutional rewrite and wealth redistribution; Fujimori offered continuity with market-oriented policies, though her family's authoritarian history complicated her appeal. Neither candidate had secured a clear majority, and a meaningful share of voters was either still deliberating or preparing to reject both.
With the margin so narrow, the outcome would likely depend less on persuasion than on mobilization — which campaign could turn out its base, hold its coalition, and capture the last wavering voices. Peru was moving toward an election with no certain answer in sight.
One week before Peru's presidential runoff, the race that had seemed settled was suddenly wide open. Pedro Castillo, the leftist teacher from Cajamarca who led Perú Libre, had been commanding the polls by ten points just days earlier. But a survey released Sunday by the Instituto de Estudios Peruanos showed him slipping to 40.3 percent support, while Keiko Fujimori, the conservative standard-bearer of Fuerza Popular, had climbed to 38.3 percent. Within the poll's margin of error—2.8 points in either direction—they were now statistically tied.
The telephone survey, conducted May 27 and 28 across 24 departments and 387 districts, captured a country in motion. Castillo's ten-point advantage had evaporated in a single week. Fujimori, facing investigation for money laundering, had closed the gap with a surge that suggested momentum was shifting her way as voting day approached. The sample of 1,227 respondents was distributed across Peru's regions with a provincial representativeness of 93.7 percent, lending the findings substantial weight.
But the numbers told a more complicated story than a simple two-person race. Blank and null votes—a form of protest against both candidates—had ticked up from 12.8 to 13 percent. More significantly, the share of voters who remained genuinely undecided had jumped to 6.3 percent from 5.1 percent the week before. Those who said they didn't know or couldn't specify their choice had fallen by two percentage points, to 4 percent, suggesting some movement off the fence, though not necessarily toward either major candidate.
The tightening reflected the volatility of a runoff that had polarized the country. Castillo represented a radical break—his party promised to rewrite the constitution and redistribute wealth. Fujimori represented continuity with the market-oriented policies of recent decades, though her family's authoritarian past and her own legal troubles made her a contested choice for many voters. With one week remaining, neither candidate had secured the confidence of a clear majority, and a significant portion of the electorate was either still deciding or planning to cast a protest vote.
The poll suggested that the election would likely be decided not by which candidate could expand support, but by which could better mobilize their base and persuade the undecided. The margin was narrow enough that turnout patterns, regional variations, and last-minute shifts could determine the outcome. Peru was heading toward a genuinely uncertain conclusion.
Citas Notables
The poll showed Castillo and Fujimori in a technical tie within the margin of error— Instituto de Estudios Peruanos survey
La Conversación del Hearth Otra perspectiva de la historia
How did Castillo lose ten points in a single week? That's a dramatic collapse.
It wasn't necessarily a collapse—it was more like the initial shock of the first-round results wearing off. Castillo had surprised everyone by making the runoff. Once Fujimori's campaign got organized and began messaging, some voters who had been uncertain or protest-voting started reconsidering.
But 40 percent is still a lead. Why does the poll say they're tied?
Because of the margin of error. With 2.8 points of uncertainty in either direction, Castillo could actually be at 43 percent or as low as 37. Fujimori could be at 41 or at 35. The gap between them is real, but it's small enough that it's not statistically meaningful anymore.
What about those undecided voters—6.3 percent? That's not huge.
It's not, but it's growing. More importantly, look at the blank and null votes climbing to 13 percent. That's a lot of people rejecting both options. In a race this tight, those protest votes matter because they're votes that neither candidate can count on.
So Castillo's lead is real but fragile?
Exactly. He's still ahead, but he's lost momentum, and Fujimori has shown she can move voters. With a week left, the question isn't whether Castillo wins—it's whether he can hold what he has.