Mr. López Obrador won the presidency with vows to end Mexico’s stubborn culture of corruption and battle its high poverty and yawning inequality.
MEXICO CITY — After 18 years of establishment politics, Mexicans decided on Sunday that enough was enough, electing the leftist candidate Andrés Manuel López Obrador as president in a landslide victory in an election of firsts.
Capturing more than half the vote, according to early returns, he won by the largest margin in a presidential race since the nation transitioned to democracy nearly 20 years ago.
Here are five takeaways from the stunning victory of Mr. López Obrador and what to expect:
To grasp the stark repudiation of the establishment, and Mr. López Obrador’s ability to capitalize on it, it is helpful to understand the recent electoral history of Mexico.
President Enrique Peña Nieto’s Institutional Revolutionary Party, known as the P. R. I., dominated politics in Mexico from 1929 until 2000, when it was unseated by the conservative National Action Party, or P. A. N., at the time led by Vicente Fox.
The arrival of a new party after seven decades of single-party rule stirred tremendous hope among Mexicans — hopes that were eventually dashed. Over the six-year term, poverty remained pervasive and corruption unchecked.
Though the party was re-elected to office in 2006, President Felipe Calderón took the nation to war, deploying the military against the nation’s drug cartels. More than a decade later, with more than 100,000 dead, violence is at record highs.
Mr. Peña Nieto appeared in 2012, a fresh-faced candidate selling a new-and-improved P. R. I. That, too, turned out to be a mirage, exposed by corruption scandals, record violence and entrenched inequality that has kept nearly half of the population living under the poverty line.
With 18 years of layered disappointments, Mexicans are hungry for change, and, perhaps, a bit of revenge. This explains why a man who has been rejected twice by the electorate — once in 2006 and again in 2012 — can fare so differently all these years later.
On Sunday night, President Trump congratulated Mr. López Obrador on his victory. “I look very much forward to working with him,” Mr. Trump said in a tweet. It was a hopeful start to a new chapter in a bilateral relationship that is arguably at its worst point in years.
Mr. Trump has badgered Mexico since he announced his candidacy, criticizing its migrants, threatening to abandon the North American Free Trade Agreement and promising to build a wall between the two countries. Reflecting the current frostiness, Mr. Trump and his counterpart, Mr. Peña Nieto, still have not met since the American president took office.
Though a leftist, Mr. López Obrador has drawn comparisons to Mr. Trump for his nationalist impulses, populist rhetoric and combative personality. But from time to time he has also displayed a pugnaciousness toward Mexico’s northern neighbor and has left no doubt that he is prepared to go toe-to-toe with Mr. Trump to defend Mexico’s interests.
The chronic ills that Mr. López Obrador railed against, propelling him to victory, now become his problems to solve.
Among them is corruption. On the campaign trail, he was short on details about how he intended to confront the problem, but said he would lead by example: His professed honesty and ethical cleanliness, he said, would flow downward through the ranks of his government and help change the nation’s culture.
He also inherits a nation reeling from rampant violence left unfettered by an anemic and corrupt public security system. More homicides were reported in May than in any other month since the government launched its current record-keeping system two decades ago, and 2017 was the deadliest year on record during the same time period.
Mr. López Obrador will also have to deliver on his promises to address widespread poverty and yawning inequality. He has laid out a development agenda that would drastically increase spending on social programs, including increasing pensions for older citizens, expanding educational opportunities for students and bolstering subsidies for farmers.
Mr. López Obrador’s victory puts a leftist at the helm of Mexico for the first time in generations, and represents a resounding rejection of the two establishment political parties that have dominated Mexican politics for the past two decades: the centrist P. R. I., and the center-right P. A. N.
The results were particularly brutal for Mr. Peña Nieto and the P. R. I., which not only lost the presidency but faces steep losses in Congress and in most state governor races. The party was once the powerhouse of Mexican politics. But Sunday’s results plunged the P. R. I. into an existential crisis, and a deeply uncertain future.
The prospects for the P. A. N. remain equally cloudy. Its candidate, Ricardo Anaya, is considered one of the most agile — and ambitious — politicians in Mexico, and with an eye on the 2024 election, he may seek to position himself as the leader of the opposition.
For as long as Mr. López Obrador has been running for president, accusations that he will sink the economy have chased him. He was likened in the news media to Hugo Chávez, the former socialist leader of Venezuela, and questionable news reports tried to link his campaign to Russia, creating a narrative of a radical and dangerous leader.
While the comparisons to Mr. Chávez are overblown and the connections to Russia totally unproven, Mr. López Obrador must still convince investors that his policies will be business friendly.
“They are far from enthusiastic but they are adopting a wait-and-see attitude,” said Duncan Wood, the director of the Mexico Institute at the Wilson Center in Washington.
Mr. López Obrador has promised an ambitious slate of social programs while assuring investors that he will exercise fiscal prudence and respect the independence of Mexico’s highly regarded central bank. In his acceptance speech Sunday night, he echoed those promises.
But how will he pay for his social programs? His advisers estimate they will eat up about 10 percent of the federal budget, or roughly $25 billion, annually. Mr. López Obrador promises to pay for his programs by cutting waste and corruption from government spending. Analysts question whether that will be enough.
