It was early in the afternoon of Oct. 22, the day of Argentina’s first-round vote, and Patricia Bullrich already knew that she’d lost her bid for the presidency.

Eliminated from the runoff, Bullrich, the pro-business candidate for the main opposition Juntos por el Cambio bloc, couldn’t sleep that night. At 4 a.m. she sent a message to Mauricio Macri, the bloc’s elder statesman, saying that she wanted to back outsider Javier Milei, according to a person familiar with her movements.

Bullrich, who earned a reputation for toughness during her time as security minister in Macri’s cabinet, sped up the announcement of her support when she learned that elements of Juntos were planning to support the other candidate, Sergio Massa of the ruling Peronist coalition, another person close to her said. She wanted to get ahead of the news, so she and her running mate came out and publicly endorsed Milei, prompting angry accusations that she was breaking her own bloc apart.

“We can’t stay neutral,” a grim-faced Bullrich said at a shambolic press conference at her party headquarters. Another cycle of Peronism of the type espoused by Cristina Fernandez de Kirchner, the polarizing former president seen by opposition parties as the symbol of all that is wrong with the country, “would condemn Argentina to greater decadence,” she said. “The country is at risk.”

It was a gamble that put Bullrich in step with the majority of Argentines as they embraced the libertarian economist’s radical plans to rescue the country from its spiral of decay, handing Milei the largest margin of victory in a presidential election in decades. A spokesman for Bullrich declined to comment on her private discussions at the time.

“The million dollar question is did Bullrich’s base like the Macri-Bullrich-Milei alliance? Yes,” said Facundo Cruz, a political consultant. “Whether the two of them read the room correctly or their voters got ahead of them, the math shows an almost exact confluence between the two political spaces.”

To be sure, the alignment of the mainstream Juntos candidate with an outsider like Milei couldn’t soften his image as an anarchist willing to blow things up. But it helped to take the sting out of the fear-mongering pushed by Massa’s campaign and to remove some of the stigma of voting for him, including moderates and those in the business community looking for direction after their preferred candidate — Bullrich — was eliminated.

For all the emphatic nature of his win, Milei’s lack of party support in Congress is a core weakness, and gives Juntos what’s sure to be an important role in helping the new government pass its platform, while shaping policy from the inside.

Another key moment in Milei’s march to the top came 36 hours after Bullrich called Macri, when she was invited to dine with both men at Macri’s sprawling estate just outside Buenos Aires.

Recalling the meeting in a radio interview, Macri said that when Bullrich arrived, he quipped “here comes the ‘montonera’” — a reference to her one-time membership of the left-wing Peronist guerrilla group that was active during Argentina’s 1970s dictatorship, a youthful dalliance that Milei used to attack her during the campaign. “The one that throws bombs,” Milei pitched in. The ice was broken and Milei and Bullrich embraced.

At the dinner, also attended by Milei’s sister and campaign organizer, Karina, Milei asked for help to win the election. It was a risk for Milei to be seen so close to an embodiment of the establishment that he’d railed against, but it helped work to soften his image and deliver the votes he needed to win.

Milei was also helped by the tack taken by Massa’s campaign in trying to paint him as dangerously out of control — “a huge strategic mistake” that backfired on election day, said Andrei Roman, the head of Sao Paulo-based pollster AtlasIntel, which correctly predicted Milei’s runoff win. For Roman, the televized debate on Nov. 12 was a milestone, not because Milei turned the tide - he clearly lost to Massa - but because the way he lost made him appear more moderate and accepting of his mistakes, while Massa came across as the career politician that he is, intent on doing whatever was needed to win.

While Milei got 30% of the vote in October and Bullrich 24%, Milei managed to mold both into 56% support in Sunday’s runoff, beating Massa who took 44%.

But the central dilemma over how to meet the expectations of his younger, angrier base, while retaining Bullrich’s more moderate electorate hasn’t disappeared and will shape his government as he struggles to balance his brand of radical eccentricity with mainstream consensus. That extends to the selection of cabinet posts as ministers are charged with delivering his agenda.

The election result suggests that most voters are relying on Milei to square that circle, and still shake things up after beating Massa’s Peronist machine.

As Mariel Fornoni, director of polling firm Management & Fit in Buenos Aires, put it: “Evidently at the last minute, people who said that neither candidate represented them ended up taking a risk and choosing what most represented change.”