Mexico is about to elect its first female president. Her job: save the nation

Sheinbaum’s commanding lead in polls ahead of Sunday’s election is rooted in her endorsement by Mexico’s popular nationalist leader, President Andrés Manuel López Obrador, who shepherded Sheinbaum’s career over the past two decades. She has given him years of unflinching loyalty in return.

At a symbolic and widely heralded event at a Mexico City restaurant last year, Sheinbaum accepted an eagle-headed ceremonial baton of command from López Obrador at a gathering of his ruling party, Movement of National Regeneration. It was a gesture to Mexico’s indigenous culture—and to voters—by a president whose approval ratings have never fallen below 60%.

“He gave me the baton, and the authority as well," the 61-year-old Sheinbaum said during a recent TV appearance.

Sheinbaum, who as former mayor of Mexico City was known for her reserved and disciplined manner, proclaims at every campaign stop that her administration will be a continuation of López Obrador’s. She echoes her mentor’s message that the government should keep a tight grip on the energy industry and guide the economy for the benefit of the poor.

Former and current Mexican officials and diplomats expect that a Sheinbaum administration would differ in style from López Obrador’s but not in substance. “There is no daylight between them," said Jorge Castañeda, a former Mexican foreign minister.

Sheinbaum occasionally signals she will be independent of her popular mentor. She has a data-driven view of governance, relying on analytics rather than charisma to continue the vision and policies of López Obrador, who operates more on gut instinct.

“We share a lot of principles, but it will be Claudia who will govern," Sheinbaum told Mexican TV, speaking of herself in third person.

The silver-haired leader, who like all Mexican presidents is limited to a single 6-year term, has said he will retire to his country home in the jungles of southern Mexico. Many voters say they don’t believe he is willing to give up his influence when his term ends on Sept. 30.

“She has been López Obrador’s obedient daughter," said Denise Dresser, a political scientist and one of Sheinbaum’s critics.

For the past six years, López Obrador has polarized Mexico, hammering opponents as rich traitors and oppressors, sometimes disclosing their confidential income and tax records. Sheinbaum has defended López Obrador against human-rights groups critical of his verbal attacks on independent media and political activists. López Obrador is thin-skinned and angered by dissent, his opponents say.

Sheinbaum is bilingual, lived in the Bay Area in her 30s and is comfortable interacting with U.S. officials and investors, according to diplomats and former and current Mexican officials. López Obrador doesn’t speak English and has little interest in affairs outside of Mexico.

If elected, Sheinbaum will have to navigate often prickly bilateral relations with the U.S., including management of Mexico’s side of the nearly 2,000-mile border separating the two countries. It is the world’s busiest in the movement of trucks and people.

She also will face the threat of powerful organized-crime groups that control the flow of U.S.-bound drugs and illegal migration, a top issue for U.S. voters. Criminal gangs are terrorizing towns and villages, the No. 1 concern of Mexican voters. Organized crime has benefited from López Obrador´s more lenient “hugs, not bullets" law enforcement policies, his critics say. The president’s administration disagrees, despite statistics to the contrary.

Mexico’s next president will have to decide in 2026 whether to continue or revise the U.S. Mexico Canada Agreement, the trade pact that propelled Mexico to become the U.S.’s biggest trading partner. “We need to keep it, protect it and ensure that it becomes one of the main pillars of Mexico’s development," Sheinbaum told Mexican bankers during a speech in April.

López Obrador forged a working relationship with the Trump and Biden administrations with efforts to slow U.S.-bound migration, which Sheinbaum is expected to continue, according to security analysts and former officials.

Yet for U.S. officials, Sheinbaum remains an enigma, said Shannon O’Neil, a senior fellow for Latin America at the Council on Foreign Relations in New York. “Is she a true believer in López Obrador’s policies or does she have differences," O’Neil said. “I don’t think anyone knows."

Life abroad

Sheinbaum grew up in a leftist, upper-middle class home in Mexico City, studying ballet and French. Her mother was a biology professor. Her father worked as a chemical engineer.

Sheinbaum’s grandparents were Lithuanian and Bulgarian Jewish immigrants who fled persecution in Europe in the early 1900s. Sheinbaum said she celebrated Jewish holidays at her grandparents’ houses as a girl, but her upbringing at home was secular. Her Jewish background hasn’t emerged as a campaign issue.

Sheinbaum accompanied her first husband, leftist student leader Carlos Imaz, to live in San Francisco from 1991 through 1995. She joined a group of about a dozen young graduate students who campaigned for the right for Mexicans living abroad to vote in Mexico’s elections, said Gaspar Rivera, another activist. Mexico granted that right in 2005, and more than a quarter million Mexicans living outside their country, mostly in the U.S., will be able to cast ballots in the June election.

Rivera recalls meetings with Sheinbaum and other activists at the janitors’ union offices in San Francisco. “She would bring her two kids to the gatherings, which were more like graduate seminars than political meetings," he recalled. Sheinbaum also helped organize Mexican migrant cherry pickers in California.

During Sheinbaum’s years in the Bay Area, she took graduate-level courses on energy efficiency at Stanford University and the University of California at Berkeley. She also conducted postdoctoral research at the Lawrence Berkeley National Laboratory.

Imaz’s political career ended after the release of a video in 2004 showing him accepting bundles of cash from a businessman with Mexico City government contracts. At the time, López Obrador was the Mexico City mayor, Sheinbaum was the city’s environmental chief and Imaz was an elected official who represented a Mexico City borough. He was later exonerated.

The couple divorced in 2016, and Sheinbaum married a college friend, Jesús María Tarriba, who works at Mexico’s central bank. Her daughter, Mariana Imaz, studied philosophy and comparative literature in Spain and California. Her stepson, Rodrigo Imaz, is a filmmaker.

Sheinbaum, who received her Ph.D. at Mexico’s national university, likes to be addressed with the honorific “Dr." She is reserved, writes her own speeches and favors PowerPoint presentations. On the campaign trail, Sheinbaum has been mocked by opponents for seeming to imitate the president’s Tabasco drawl.

López Obrador, the son of a provincial shopkeeper, is comfortable giving rambling, improvised news conferences.

Polls show Sheinbaum with a double-digit lead over Xóchitl Gálvez, a senator and rags-to-riches businesswoman of indigenous background. Gálvez, who is running as the candidate of a three-party opposition coalition, refers to Sheinbaum as the “Ice Lady." A spokesman for Sheinbaum said she has a great sense of humor.

Deadliest cities

Organized-crime groups control about a third of Mexico, according to U.S. Northern Command. More than 200 gangs extort businesses and run drug-trafficking and human-smuggling routes, terrorizing residents and killing thousands caught in the crossfire of internecine warfare. The six deadliest cities in the world are in Mexico, said Eduardo Guerrero, a security consultant who served in Mexico’s federal security ministry.

Sheinbaum has defended López Obrador’s security strategy, calling the war on drugs launched by Mexico’s previous presidents a disaster. López Obrador has curbed the operation of U.S. law enforcement officers in Mexico and accused the U.S. Drug Enforcement Administration for fabricating drug charges against Mexico’s former defense minister.

Diplomats say that as mayor of Mexico City, Sheinbaum showed her independence from the president. Her senior security officials developed a close working relationship with U.S. law enforcement agencies. Mexico City police used intelligence from the U.S. Homeland Security Investigations agency to seize 1.6 tons of cocaine two years ago, U.S. officials said. It was a record seizure in Mexico’s capital, which is a transshipment hub for U.S.-bound drugs.

Security analysts credit Sheinbaum with slashing the number of homicides and other crimes in Mexico City by boosting public-security spending. She improved police training programs, increased the number of police officers and raised salaries.

Mexico City’s murder rate stood at 8.45 per 100,000 inhabitants last year, similar to the rate in Los Angeles, said Guerrero, the security consultant. Sheinbaum said her security achievements can be replicated across the country if she becomes president.

Party control

Lopez Obrador cobbled together his party, Morena, a decade ago from leftist groups and went on to win the 2018 presidential election. Morena is an acronym that refers to Mexico’s dark-skinned religious patron, the Virgin of Guadalupe. It now governs 23 of Mexico’s 32 states, an echo of Mexico’s single-party rule that ended in 2000.

The president’s opponents call him an authoritarian and question whether Sheinbaum will be able to control the party after his departure.

Sheinbaum has backed proposed constitutional overhauls that many Mexicans said would hobble the country’s democracy. One proposed change would dismantle Mexico’s electoral institute, which has played a large role in transforming Mexico from a one-party state.

Another constitutional change would have voters elect federal judges including to the Supreme Court, putting their independence at risk.

“Mexico’s political pluralism is at stake," said Ricardo Becerra, the president of the Institute of Studies for a Democratic Transition, a Mexico City think tank.

Sheinbaum has the opposite view. A campaign spokesman said the proposed overhauls aim to strengthen Mexico’s democracy and the judiciary.

To expand Mexico’s economy, Sheinbaum wants to develop 100 industrial parks and attract manufacturing plants leaving China. That might be impossible if she continues to support López Obrador’s energy policies restricting foreign and private investment. Sheinbaum favors state-run companies. She also seeks to reduce dependence on imports through self-sufficiency.

“The time of privatization is over," Sheinbaum has said. “Never again."

Yet she hopes to attract billions of dollars in private investment for solar and wind farms, with the government keeping control and a majority share in the electricity market, a Sheinbaum adviser said.

López Obrador sought to reverse the opening of the energy industry to foreign and private investment carried out under his predecessor. He has halted renewable energy projects that were almost completed. López Obrador pushed laws to favor the state-run oil and electricity companies, but many of the changes were blocked by Mexican courts.

López Obrador’s hostility to foreign investment in energy has led to trade tensions with the U.S., which has been largely unwilling to press the issue given the Biden administration’s overriding interest in obtaining Mexico’s help in containing the flow of illegal migrants, diplomats and analysts say.

Polls show that Morena is unlikely to win a two-thirds majority in both houses of Congress required to change the constitution. That might give Sheinbaum a better chance to set her own path.

“An overwhelming victory in the congress would be Lopez Obrador’s victory," said Alejandro Schtulmann, a Mexican political analyst. “The legislators would be beholden to him. Her agenda would be limited to Lopez Obrador’s agenda."

Write to José de Córdoba at jose.decordoba@wsj.com and Santiago Pérez at santiago.perez@wsj.com