If progressive populist Andrés Manuel López Obrador (or AMLO, as he is widely known) wins Mexico’s presidential election on Sunday—which seems almost inevitable now, given his daunting lead in national polls—it will be due, in large part, to disgust with the ruling Institutional Revolutionary Party (PRI) in the impoverished southern states of Mexico.

A popular former Mexico City mayor, López Obrador has made it a point to visit every municipality in the country, expanding the base of support that propelled his previous, unsuccessful runs for president, in 2006 and 2012, to include the social movements in Mexico’s south.

In a huge June 16 rally on in a field behind a cement factory on the outskirts of Oaxaca City, the candidate spoke to an adoring crowd. Projected on jumbotrons in a white shirt, with a garland of flowers around his neck, he promised a new jobs program to pave the roads in the majority of Oaxaca municipalities that lack this most basic amenity. His director of programs for indigenous communities will be Oaxacan, and his secretary of social development will be based here, he announced, to cheers from the crowd. His government will finish the long-delayed highway projects connecting Oaxaca City to the ports of Salina Cruz and Puerto Escondido on the Pacific Coast, he added, saying of those unfinished projects, “It’s shameful how the government has robbed the people.”

“We will do away with the misnamed education reforms,” López Obrador declared—an important message to Oaxaca’s militant teachers union, which has made resisting PRI president Enrique Peña Nieto’s education-reform program, and its mandate that teachers pass a test to keep their jobs, a centerpiece of its activism.

By focusing on the real problem—poverty in rural, indigenous communities—instead of making teachers pass competency tests, “We’ll have a plan for education that makes things better without compromising labor rights,” AMLO told the crowd.

“The problem is not here. The problem is at the top,” he continued, slipping into his familiar stump speech. “Right now there is a mafia in power that is oppressing all of the people…. Only the people can save the nation.”

This kind of talk has been making US investors nervous. The editorial board of The Washington Post has compared López Obrador to Donald Trump—a dangerous populist determined to undo the accomplishments of his more mainstream predecessor. Financial Times quoted anonymous business leaders who fear that an AMLO administration will turn Mexico into a new Venezuela.

But the people who came out to see López Obrador in Oaxaca told me, over and over, that they were fed up with the status quo under Peña Nieto. Warnings that AMLO will ruin what The Wall Street Journal calls “a rising middle class that has widely benefited from economic modernization” had little resonance.

The truth is, Mexico’s deep social inequality, which leaves poor people not only economically stranded, but enduring rising violence while the wealthy retreat behind private security guards, has provoked a major backlash. Like a Mexican Bernie Sanders, AMLO has tapped into the discontent of a large swath of voters—including a larger share of young people than any other candidate—who feel they are being left behind while the rich get richer.

Toward the end of the campaign, even the PRI itself seemed to have recognized the inevitable. “Working hard to regain your confidence!” declared a PRI campaign slogan spray-painted on a wall in one small town.

The PRI’s current strategy, AMLO told his supporters in Oaxaca, is to try to get voters to split the ticket—to support AMLO for president, but vote against his MORENA party candidates downballot, hence denying him the legislative support he needs to accomplish his agenda. “Don’t buy it!” he urged the crowd. “Raise your hand if you are going to vote across the board!”

“The movement has been building for a long time. People are sick and tired of the corruption, the impunity—all the damage,” said Elida Castillo, a housemaid who came out to see AMLO in Oaxaca.

López Obrador, with all of his travels to forgotten little towns, understands the struggles of poor people, said Castillo. “He knows our feelings,” she said. “The people in government don’t know what we feel. They have rich parents, and they spend their time sitting behind a desk.”

Nowhere is the corruption and fecklessness of the current regime more keenly felt than in the devastated Isthmus region of Oaxaca, where thousands of families are still homeless nine months after the September 2017 earthquakes.

The government handed out cash cards to help some residents rebuild their homes. But when they took the cards to the bank, they discovered that there were no funds attached.

Today, only 35 percent of the schools in Oaxaca that suffered severe to moderate damage in the earthquakes have been repaired.

“Teachers are holding class outside, under trees, with no bathrooms,” said Elsa Guzman Cruz, a retired teacher in Oaxaca, and one of thousands of educators who poured into the streets for the nationwide teachers’ strike in May, stopping traffic in Oaxaca City, where teachers set up a protest encampment in the central square.

“There’s a discontent in all sectors of society,” said Wilber Valdivieso, the spokesman for Oaxaca’s radical teachers union, Seccion 22. He grew up in the Isthmus region and had just returned from a visit to the teachers who are holding class outside their ruined schools. “People see the government is not coming through, not making good on its promises.”

Valdivieso sat in his office—a cubicle with flimsy walls covered with posters of Mexican revolutionaries, in a rundown office building in downtown Oaxaca, as teachers filled the streets and camped outside the building. They were protesting Peña Nieto’s education reforms as well as the government’s witholding of teachers’ wages and pension payments, and the failure to rebuild the schools after the earthquakes.

The PRI will lose the July 1 elections, Valdivieso predicted, thanks to what he called the “Peña Nieto effect.”

“There’s a new political economy of the country. It doesn’t benefit most people,” Valdivieso added.

The crackdown on unions, as well as economic reforms that open up Mexico’s natural resources to extraction by foreign companies, have benefitted “those at the top,” as AMLO puts it, not the poor communities embroiled in struggles over land rights with the mining companies and other resource-extracting firms. These battles have fed the militancy in southern Mexico, from the Zapatistas’ struggle in Chiapas to the hundreds of skirmishes over land rights in Oaxaca.

Oaxaca, Chiapas, and other southern states “are the richest in natural resources, and it is most convenient for the rich people to be able to rob them of all that treasure,” said Guzman Cruz, who, like other teachers I spoke with, moved quickly from talking about education reform to addressing other attacks on the public sector. “Look at the mining, the water, the logging, even the air—with the big wind-energy plants,” she added. “The teacher, who is in contact with the poor people in the communities, understands this and protests it.”

Elida Castillo, the housemaid at the AMLO rally, put it this way: “They have privatized everything. And the fight against workers is doing us in.”

López Obrador’s supporters are galvanized by the same rhetoric—about “those on top,” and “the mafia of power”—that is worrying the powerful in Mexico City and Washington, DC.

To calm fears about an imminent revolution, Carlos Urzúa, López Obrador’s economic adviser and likely the future head of the Mexico’s finance ministry, has been traveling around the United States, meeting with reporters, farmers, think-tank experts, and business executives. A friendly, white-haired man with an impish laugh, Urzúa recieved his PhD in economics from the University of Wisconsin and taught at the Woodrow Wilson School at Princeton. He is well suited to his diplomatic mission. The López Obrador administration believes in maintaining international trade agreements and will not cancel contracts with foreign oil companies or seek a constitutional reform to nationalize the energy sector, he says.

Sitting in his Mexico City office as news about Donald Trump’s aggressive treatment of both Mexico and Canada made headlines, he chuckled at the poetic justice of the punitive tariffs Mexico has slapped on US exports from Republican states, retaliating against Trump’s tariffs on Mexican goods. But Urzúa nonetheless renounces “any trade war, no matter how small.” Trade wars can escalate with damaging consequences, he said. Above all, Mexico needs robust international trade to grow. Citing an abysmal poverty rate and anemic economic-growth statistics, he added: “If we want to combat poverty, we have to grow, and to grow we need to have economic investment, both foreign and domestic.”

The López Obrador administration will seek a new NAFTA agreement. At the same time, Urzúa added, the new administration plans on investing heavily in social programs and subsidies to help the small farmers who have lost their livelihoods because of NAFTA. The new government will find funding for a raft of anti-poverty programs by rooting out waste and corruption in government procurement, and by slashing the salaries and pensions of top government officials, he said.

Given the long history of fraud and corruption in Mexican elections—and López Obrador’s famous rebellion after the 2006 election, in which he challenged the legitimacy of the outcome and set up a protest encampment in Mexico City—a lot of people are nervous.

The teachers union in Oaxaca is collaborating with citizens’ groups on election-monitoring efforts. And Valdivieso is optimistic. “By listening to the people, Andrés Manuel is opening up possibilities,” he says.

At the end of the rally in Oaxaca, the candidate promised to stay in touch. “Before they put the presidential sash on me, I am going to come back to Oaxaca, as your president-elect,” he declared.

The crowd ate it up. “Together we will make history!” they chanted.

“Just as you love me, I love you, and a little more besides,” López Obrador told the crowd.

Then he flew off to his last campaign stops, before the end of an election year his supporters hope will finally bring they change they crave.