Politics and law clash in Mexico City

After a tumultuous week in which the Mexico City mayor's political opponents tried to jail him, and more than a million supporters took to the streets to decry what they call a political witch hunt, Andrés Manuel López Obrador returned to City Hall Monday.

It was just another day at the office - except for the fact that, as his critics maintain, he is no longer mayor.

Mr. López Obrador is under criminal investigation for a land dispute, effectively barring him from his job. But he's also the leading candidate for president next year - that is, if he can even run. Mexican law prohibits anyone under indictment from seeking high office.

On one level, the López Obrador saga is a political "he said, she said." Did he break the law in 2001? Is the ruling party trying to crush a popular left-leaning politician? But at its heart, say supporters and detractors alike, it's the story of a fragile democracy wrestling with the rule of law, the impunity of powerful politicians, and past perceptions that the courts can be used to stifle political opponents. "This is a witch hunt," said Sergio Ponce, a car attendant, at Sunday's march. "We deserve to choose our own leaders," his cousin Ernesto chimed in. "We are not a dictatorship here."

Mexico City police, who work under López Obrador, estimated that some 1.2 million demonstrators were on the streets Sunday, ranking it among the largest protests in Mexican history. The well- organized, peaceful show of force was a testament to the power of the charismatic 51-year-old mayor, who leads the left-leaning Democratic Revolution Party (PRD) and has won the adoration of the masses with cash handouts to the elderly, poor, and single mothers; by building playgrounds, schools, and new roadways; and by thumbing his nose at the establishment.

It was just such an attitude that got him in trouble in the first place. Four years ago he ignored a judge's order to stop building an access road to a hospital that ran over private land. "In a country where breaking the law is a national pastime, this is nothing," says Vidal Mendoza, a lawyer who does not support López Obrador, referring to times when the government diverted money from the state-owned oil companies into political campaigns and banks handed out loans to political pals, all with no prosecutions. "To go after López Obrador is sheer insanity, and is clearly nothing more than a political maneuver."

And yet go after López Obrador is what President Vicente Fox's National Action Party (PAN), together with the other main rival party, the Institutional Revolutionary Party (PRI), has done. On April 7, the Mexican Congress stripped López Obrador of his immunity so he could stand trial for abuse of power. A few days later, the attorney general's office filed felony charges against him, which should have led to jail time. Except that two members of Mr. Fox's party - one the niece of the presumed 2006 PAN presidential candidate - immediately posted the $180 bail, possibly in an effort to keep the mayor from increasing his martyr status.

"I am going to dedicate myself to working," the mayor said Monday, before returning to City Hall. He flashed the victory sign to waiting supporters.

"The return of Mr. López to the mayor's office ... is a provocation and a violation of the laws," said Ruben Aguilar, a spokesman for Fox.

As all this takes place, López Obrador remains stuck in a political limbo - most interpretations of Mexican law prohibit anyone facing criminal charges from holding, or even running for, elected public office. In a country where cases can be drawn out for months or even years, it isn't clear that the trial against the mayor, if it indeed takes place, will be finished when the time comes to register presidential candidates early next year.

The mayor's critics oppose his leftist policies, complain about his seeming disregard of laws he doesn't like, question where he gets the money for his populist projects, and compare him to Hugo Chávez, the leftist Venezuelan leader whom the United States labels a dictator. But those same critics say that taking him out of the race on such a small issue is a mistake. "His power has increased tenfold," says Mendoza. "There is no doubt he will now become president. If not in this election, then in the one afterwards."

According to the most recent poll, if elections were held today, López Obrador would get 38 percent of the vote, up from 35 percent in February and 10 percent more than his two main rivals. And 72 percent say they believe that Congress's action was politically motivated, rather than part of a legal proceeding. Some 60 percent said they would take part in acts of civil disobedience to support the mayor.

The clear loser in the saga appears to be Fox and the ruling PAN party. Fox came to power in 2000 after seven decades of authoritarian rule by the PRI, promising a new dawn of the democratic process and rule of law. Today, the perception that Fox is trying to use his power to ensure his party stays in office - just as former PRI presidents before him - might be the final chapter in his legacy. In the past few weeks there have been protests against Fox, ranging from a hunger strike outside the presidential residence to a rowdy demonstration at his family's ranch in central Mexico.

The PAN says that by going ahead with the prosecution it shows that no one, however popular, is above the law. "A crime is a crime," Foreign Minister Luis Ernesto Derbez said last week. "To say a minor crime shouldn't be prosecuted ... is terrible in our country, because it implies that respect for the law is a respect that is qualified."

• Ms. Harman is the Latin America bureau chief for the Monitor and USA Today.