Sheinbaum is facing Xóchitl Gálvez, 61, a tech entrepreneur with Indigenous origins. She’s promised to spur economic growth and curb the rising power of organized crime groups, evident in the scores of attacks on candidates and their aides during the campaign. Gálvez represents a coalition of traditional parties that have struggled to catch up to the juggernaut that is López Obrador’s Morena movement.

The election in the United States’ most populous neighbor has important consequences. Mexico is the No. 1 U.S. trading partner, and key sectors of the countries’ economies — from auto manufacturing to the cultivation of berries and avocados — are intertwined. Mexico is also a crucial funnel for migrants and drugs such as fentanyl and cocaine bound for the U.S. border.

“This is a vital election because the two main candidates represent two contrasting visions of government and radically different visions of the world,” said Luis Rubio, chairman of the policy think tank México Evalúa.

Gálvez has blasted López Obrador for weakening institutions such as the federal electoral agency and eroding checks and balances. “We’re going to bring freedom, whereas an authoritarian government wants to impose its decisions,” she said last week.

Sheinbaum has promised to expand the social programs of López Obrador, who is limited to one term by the constitution. She’s pledged to maintain the North American free-trade treaty when it comes up for renegotiation in 2026, but says the economic changes of recent decades have created “starvation wages.”

“After 36 years, it is clear that a country cannot advance when it favors the most prosperous,” she said.

Voters on Sunday will also choose 500 federal deputies and 128 senators, the mayor of Mexico City, eight governors and more than 20,000 officials at the state and local level.

Mexico will have a female president before the U.S.

The election will almost certainly give Mexico its first female president. The lone man in the race — Jorge Álvarez Máynez, 38, from the small, center-left Citizens’ Movement party — is running a distant third in polls.

Women in this traditionally macho country didn’t win the right to vote until 1953, three decades after their American counterparts. But with the adoption of gender quotas and a gender-parity law during Mexico’s transition from a one-party state to democracy, women now hold half of the seats in Congress, and nearly one-third of the governorships.

Starting in October, one will occupy the presidency.

“This will have an enormous impact,” predicted the writer Sabina Berman, a prominent feminist. “Boys and girls will now know that girls can become anything they want, depending on their talent, their efforts. And that, in a country as violent and historically machista as Mexico, is an enormous thing.”

If Sheinbaum wins, she’ll also be Mexico’s first Jewish president.

Election raises concerns about Mexican democracy

While two women have headlined the presidential race, the most pressing issue involves a man — López Obrador. The folksy, silver-haired president shook up Mexico with what he called the Fourth Transformation, a program aimed at helping the lower classes and protecting symbols of national pride such as oil and corn from foreign competition.

López Obrador has doubled the minimum wage, increased benefits for the elderly and vulnerable, and poured money into Mexico’s heavily indebted state oil company. In a country of vast income inequality, he won over ordinary Mexicans with visits to villages and hardscrabble neighborhoods, pressing the flesh and promising public works. At daily news conferences, he blasted his perceived enemies — old-school politicians, journalists and critics.

The percentage of Mexicans expressing confidence in the national government doubled in five years, reaching 61 percent last year, according to Gallup. That’s twice as high as in the United States.

The opposition accuses López Obrador of re-creating the sort of imperial presidency that ruled Mexico for most of the 20th century, and demonizing the middle class and the wealthy. Of particular concern are his efforts to diminish the power of institutions that have opposed him, including the judiciary. He’s proposed replacing the Supreme Court with judges picked by popular vote, an idea Sheinbaum has embraced.

“What’s at risk with a Morena triumph is our democracy,” said Carlos Bravo Regidor, a political analyst.

Sheinbaum has dismissed such concerns. “Our project is to defend democracy, liberty and the dignity of the people,” she said in a closing rally Wednesday.

How Mexico’s next president will work with the U.S.

Mexico’s next president will play a significant role on issues critical to Washington, such as migration and drug trafficking.

López Obrador became an important ally of presidents Donald Trump and Joe Biden in trying to decrease the flow of U.S.-bound migrants. Bilateral efforts on drugs have been rockier; López Obrador scaled back cooperation with the U.S. Drug Enforcement Administration, accusing it of violating Mexico’s sovereignty, and failed to rein in the trafficking of deadly fentanyl to the United States.

Sheinbaum and Gálvez both have pledged to maintain good relations with the United States and to prioritize the fight against violent cartels and gangs. Sheinbaum’s platform includes beefing up the intelligence capabilities of security forces and increasing cooperation between police and prosecutors. Gálvez says she’d work more closely with U.S. authorities, and increase resources for local police.

Both candidates talk of promoting near-shoring, the trend of companies moving production from China and other countries to Mexico to be closer to the U.S. market. But the power grid here is already overwhelmed, and international firms have accused López Obrador of discriminating against them in the generation of energy, particularly renewables.

The cartels’ fight for territory threatens Mexico’s stability

Voters’ biggest critique of López Obrador is his failure to halt the expansion of organized crime activity. While homicides have dipped since he took office, according to official statistics, crime groups are taking de facto control of more land and economic activity. They’ve moved beyond drug trafficking to a host of other illegal enterprises, including the extortion of businesses ranging from sprawling cattle ranches to tiny tortilla shops.

More than 230 candidates, their relatives and aides were assassinated during the current electoral cycle, the consulting firm Integralia has reported, as cartels have fought to install allies in mayors’ offices.

The next president will face another challenge: maintaining political stability. López Obrador, a savvy political operator, has kept Morena’s competing factions in check. Sheinbaum doesn’t have the same influence in the party, which was founded as a vehicle for López Obrador’s ambitions.

“Claudia is going to have this problem” if she wins, said Alejandro Rojas Díaz Durán, a senator who recently broke from Morena. “She’s not Andrés. She is an efficient administrator, but not a political administrator like Andrés.”

Lorena Ríos in Monterrey, Mexico, and Isabel Maney in Mexico City contributed to this report.