Mexicans are heading to the ballot box in a potentially transformative election that could put in power a firebrand vowing to end business as usual in a country weary of spiralling violence, unchecked corruption and scandal-plagued politicians.
But his rivals warn that a victory by leftist Andres Manuel Lopez Obrador could set the country back decades with an interventionist economic policy and are also promising to fight corruption and bring change to Mexico.
All the candidates are lambasting US president Donald Trump’s policies against migrants and Mexico.
It is Mr Lopez Obrador’s third bid for the presidency and some see it as his best shot after 12 years of near-permanent campaigning.
His railing against the “mafia of power” that has long ruled Mexico and in favour of the poor appears to be falling on receptive ears with polls showing him with a wide lead over three rivals who have failed to ignite voters’ interest.
Much of the popular ire has been aimed at unpopular president Enrique Pena Nieto’s Institutional Revolutionary Party.
Its candidate, Jose Antonio Meade, failed to gain traction with voters who would not give him the benefit of the doubt in spite of his ample resume in government and being an outsider to the ruling party.
Ricardo Anaya is the candidate of a right-left coalition. He has tried to harness the youth vote with an emphasis on technology and new ideas, but he divided his own conservative party to take its candidacy and it is unclear if his new allies in the leftist Democratic Revolution Party will actually turn out for someone from the other end of the ideological spectrum.
Juan Carlos Enriquez, 30, said he supports Mr Lopez Obrador but warned him that he better not steal.
“Of course, I want him to win. But it has to be made clear that he has to deliver what he promises and not become like the rest,” he said.
Hovering over the election is the spectre of vote fraud, though electoral officials deny it is a possibility with the modern balloting technology and institutions now in place.
In both of Mr Lopez Obrador’s previous two presidential losses he alleged fraud. In his first loss — by a mere 0.56% to conservative Felipe Calderon in 2006 — his supporters held months-long protests in Mexico City and he referred to himself as “the legitimate president”.
His allies are warning even before Sunday’s presidential vote that there better not be any funny business.
“They shouldn’t dare commit a fraud, because if they do they will meet the devil,” said Yeidckol Polevnsky, president of Mr Lopez Obrador’s Morena party. “We will not accept it.”