Mexican voters angry and frustrated over corruption and violence delivered an emphatic victory to leftist Andres Manuel Lopez Obrador in the presidential election.
The win gives him a broad mandate to upend the political establishment and govern for the poor.
Early on Monday, with about 50% of the votes counted, his advantage was close to the quick count’s statistical sample.
A prominent exit poll predicted that his party allies were poised to score big victories in congressional races, possibly winning absolute majorities in the Senate and the Chamber of Deputies.
Mr Lopez Obrador, who campaigned on vows to transform Mexico and oust the “mafia of power” ruling the country, rode widespread voter anger and discontent with the governing Institutional Revolution Party, or PRI, of President Enrique Pena Nieto and had led opinion polls since the beginning of the campaign.
The PRI, which dominated Mexican politics for nearly the entire 20th century and recaptured the presidency in 2012, was set to suffer heavy losses not just in the presidential race but in other polls as well.
In brief remarks at a hotel in central Mexico City, Mr Lopez Obrador called for reconciliation after a polarising campaign and promised profound change but with respect for the law and constitutional order.
“I confess that I have a legitimate ambition: I want to go down in history as a good president of Mexico,” he said, after losses in the previous two elections. “I desire with all my soul to raise the greatness of our country on high.”
“This new national project will seek to establish an authentic democracy and we do not intend to establish a dictatorship,” he said. “The changes will be profound, but in accordance with established order.”
Conservative Ricardo Anaya, of a right-left coalition, and the PRI’s Jose Antonio Meade acknowledged defeat shortly after polls closed nationwide. The quick count had them on around 22% and 16% respectively.
Mr Lopez Obrador’s supporters began wild celebrations in Mexico City, cruising up and down the central Paseo de la Reforma boulevard honking horns to the tune of “Viva Mexico!” and waving Mexican flags from car windows and sunroofs.
Retired teacher Susana Zuniga beamed and said the country was experiencing a moment similar to the Mexican Revolution a century ago.
“The people are fed up. That is what brought us to this,” she said.
US President Donald Trump tweeted congratulations: “I look very much forward to working with him. There is much to be done that will benefit both the United States and Mexico!”
Mr Lopez Obrador said individual and property rights would be guaranteed, promised respect for the autonomy of the Bank of Mexico and said his government will maintain financial and fiscal discipline.
He said contracts obtained under energy reforms passed under President Nieto will be scrutinised for any corruption or illegality, but otherwise contracts will be honoured.
“There will be no confiscation or expropriation of assets. … Eradicating corruption will be the principal mission,” he said.
He said he will seek a relationship of “friendship and respect” with the United States. And rather than the use of force to fight spiralling violence, he will look to fix root causes such as inequality and poverty.
“Peace and tranquility are the fruits of justice,” he said.
Mitofsky predicted Morena allies would take between 56 and 70 seats in the 128-member Senate and between 256 and 291 in the 500-seat lower house.
“The anger that the average Mexican feels toward the way things are being governed has favoured Lopez Obrador,” said Shannon O’Neil, senior fellow for Latin America Studies at the Council on Foreign Relations. “He’s been able to capture the mantle of the person who’s on the outside who wants change.”
He also pledged to increase support payments for the elderly and to give scholarships or paid apprenticeships to young people.
“Now that he has won, he cannot fail this new generation that believes in him,” said Mariano Bartolini, a 29-year-old lawyer who voted for Mr Lopez Obrador in the north-western city of Rosarito, near Tijuana.
“It is thanks to us young people who are supporting him that he was able to get more votes than he did in past elections.”