Leopoldo Lopez won his last election as mayor of an affluent Caracas district with 81 percent of he vote. Women supporters mobbed him at a recent Mother's Day appearance, posing for photos while he and his wife handed out roses.

But the popular politician's plan to challenge incumbent Juan Barreto, mayor of Greater Caracas, later this year could be thwarted by 26 criminal charges against him — accusations Lopez says were trumped up by an operative of President Hugo Chavez.

He's not alone.

Nearly 400 others — mostly opposition politicians — have been barred from running for office in state and municipal elections in November by Venezuela's top anti-corruption official, a close Chavez ally.

Comptroller General Clodosbaldo Russian made public what critics call a "blacklist" of candidates in February. Though none has been formally charged with a crime, Russian argues that law allows him to prohibit all 386 from running for office while he investigates charges ranging from nepotism to illegally awarding public contracts.

Opposition leaders say they have never seen such a bold attempt to block their candidacies since Chavez took office nearly a decade ago. But as soaring crime and double-digit inflation eat away at Chavez's popularity, many say his allies may be having a harder time riding his coattails into office.

"Chavista candidates can no longer expect to win simply because they're on the president's bandwagon," said Luis Vicente Leon, a political analyst at the Caracas-based polling firm Datanalisis. "The list takes opposition leaders who pose threats in some regions out of the way."

Russian, a leftist activist who was imprisoned in the 1960s under a counterinsurgency crackdown, did not respond to repeated requests to be interviewed.

But Chavez ally Willian Lara denied that the list is politically motivated, saying that Russian's sole objective is to fight corruption "wherever it's found."

He called opposition candidates hypocrites.

"They say they support the fight against corruption. But when public institutions impose sanctions, they launch disinformation campaigns," said Lara, a former Chavez information minister.

The politicians on Russian's list have appealed to the Supreme Court to overrule him, arguing that that their civil liberties are being violated.

The stakes are high. Chavez allies currently control all but four of Venezuela's 23 state governorships and most of its 300 municipal posts. But the socialist president is still feeling battered from his first electoral defeat last December on a referendum that would have expanded his powers, created new forms of communal property and allowed him to run for re-election indefinitely.

In Lopez's case, Russian is investigating accusations that the Chacao district mayor misspent public funds and guided a donation from Venezuela's state oil company to a nonprofit group led by a close associate.

Among the remaining 24 allegations, Lopez faces a charge of rebellion for permitting anti-Chavez military officers to occupy a city plaza in 2002 and 2003. He says it was the federal government's job to remove the soldiers, not his. And he dismisses the other charges — which include building-code violations and instigating violence — as unfounded, arguing that the list amounts to "political retaliation."

"Why do they announce these cases now? Because I can win elections," he told The Associated Press.

Nobody in the opposition has much faith in the Supreme Court, whose justices were appointed by the Chavista-dominated National Assembly and are widely perceived to be government-friendly.

Russian brushes off the possibility of a Supreme Court reversal.

"For now, the Comptroller's Office has the final word," he recently told state television.

Still, a legal challenge may be the opposition's only recourse. Its leaders say Venezuelan law requires the court to decide before Aug. 23, when candidates must register with the electoral council.

That five-member board is also awaiting the Supreme Court decision.

Chavez hasn't publicly addressed the dispute, though he has said his "revolution depends on the elections in November." He has warned supporters that widespread upheaval, including street protests, could result if opponents win key offices.

Meanwhile, Lopez is undeterred in his campaign.

The 37-year-old graduate of Harvard's Kennedy School of Government, seen by supporters as an efficient administrator, is campaigning in poor barrios and making inroads in areas once considered Chavez strongholds.

Plastered around Caracas are blue campaign posters showing a smiling Lopez and predicting that "Change is coming."

But with the legal case he faces, that remains to be seen.