Newspapers at a street vendor’s stall Monday in Valle de Chalco, Mexico, trumpet Andrés Manuel López Obrador’s victory. (Bénédicte Desrus for The Washington Post)

Inés Villa has been waiting since childhood for a president like Andrés Manuel López Obrador, who has been swept into office in a landslide by millions of the working poor like her.

Growing up in Valle de Chalco, a once forlorn squatter settlement on the fringe of Mexico City, the 34-year-old shopkeeper and mother of two remembers carrying water from a single community tap, walking to school on muddy, unpaved streets, helping her mother wash clothes in a drainage ditch.

All that began to change when Valle de Chalco was made the poster child of the federal government’s social investments programs three decades ago, by a president accused of winning his election fraudulently. A torrent of money paved streets, installed sewer, water and power lines, built schools.

Such largesse long kept Valle de Chalco and thousands of communities like it across Mexico loyal to the long-ruling Institutional Revolutionary Party, or PRI, and later to its political rivals that emerged through a fitful generation-long transition to democracy.

But that fealty was buried in Sunday’s election — perhaps for good — as voters overwhelmingly shunned the PRI and its traditional left and right rivals to place their faith in López Obrador, a leftist nationalist who is sharply critical of what he calls the “mafia of power” — career politicians and their allies in the business community.

The vote provided a clear signal of how pocketbook politics have become less powerful as the country has experienced rampant corruption, unhinged criminal violence and deep inequality amid an industrial boom.

Inés Villa serves a customer Monday at her store in Valle de Chalco. (Bénédicte Desrus for The Washington Post)

“The PRI did a lot for this town over the years, really improved things,” said Villa, whose tiny grocery stands across the street from the field where Pope John Paul II once celebrated Mass to underscore the plight of Mexico’s poor. “But as the years have passed you see how they have robbed, cheated, lied and failed.

“A change has to happen,” she said.

Still-incomplete returns Monday had López Obrador winning some 53 percent of the nationwide vote in a four-way race. He was ahead by a slightly larger margin in the state of Mexico, which envelopes the capital and includes Valle de Chalco and other raw bedroom communities.

The coalition led by López Obrador’s National Regeneration Movement, or Morena, also won the largest bloc in Congress, probably giving him a clear mandate to implement the policies he says will be aimed at lifting the fortunes of people in places such as Valle de Chalco.

López Obrador’s closest rival, with the center-right party that held the presidency for the first dozen years of this century, trailed by 30 points. The candidate of the PRI, which autocratically ruled Mexico state for most of the past century, had won just 16 percent.

Sunday’s vote accelerated the long decline of the state of Mexico as a bastion of the old politics and vote-piggy-bank PRI. President Enrique Peña Nieto’s political machine, based in his hometown in the state, was considered Mexico’s most adept. The PRI has held the statehouse since the party’s founding 89 years ago.

“The same parties that assured Mexico a gradual transition to electoral democracy are today roadkill,” said Federico Estévez, a political scientist in Mexico City who has tracked the country’s political transition for the past three decades. “A majority of the electorate has said, ‘Good riddance!’ ”

“Mexico faces stormy times as government and business duke it out for several years,” Estévez said. But, he added, with luck, the election results can lead to a “long-term foundation for sustained support of the political system on the basis of a new social contract.”

That new contract has begun to flower here, political activists say, as neighborhood groups that long bartered votes for the PRI — and more recently the leftist Party of the Democratic Revolution — for public works have been replaced by politics waged on social media by teens and grandmothers alike.

Evaristo Lopez, second from left, and his friends discuss the meaning of López Obrador's victory in Valle de Chalco. (Bénédicte Desrus for The Washington Post)

“When you reach a certain level of well-being, the old politics don’t work anymore,” said Evaristo Lopez, a 53-year-old electrician who joined the Morena party at its founding four years ago. “People have many more sources of information, opinion and organizing now. The old ways don’t have the same power.”

Poverty still prevails here, certainly.

But the flood of government money through the past three decades has transformed most of Valle de Chalco from tin-shacked squalor into a bustling city of 400,000.

Shops selling everything imaginable line streets clogged with late-model cars and death-defying motorcycle taxis. Rows of one-story raw-cinder-block homes sit aside the well-kept, multistoried houses of the wealthier residents. Gleaming shopping malls, technical schools and a state university branch underscore the community’s middle-class aspirations.

Motorcycle taxis in the streets in Valle de Chalco. (Bénédicte Desrus for The Washington Post)

But dissatisfaction with the status quo has grown along with the greater prosperity. Freed from worrying about a roof, a bed and a daily meal, many residents have turned their sights to larger issues. López Obrador’s nationalist message and criticism of Mexico’s globalized economy struck a nostalgic nerve with many.

“We don’t love our traditions. We don’t love our culture. We have given up our economy,” said David Villarreal, 31, a dreadlocked bicycle-shop worker who stood two hours under a hot sun Sunday to cast his vote for López Obrador. “It’s a question of national identity.”