CARACAS, Venezuela — During his 14 years in power, Hugo Chavez has built a reputation as one of the most aggressive and effective campaigners in the hemisphere, easily winning his last three elections. “Hurricane Hugo” was known for his energetic, back-slapping style that had him plunging into throngs of supporters and electrifying crowds.

This year, however, his campaign seems to have been downgraded to a tropical storm, as Chavez, 58, has kept most appearances tightly scripted and, for the most part, close to the Miraflores presidential palace.

On Monday, he briefly high-fived supporters and hugged a baby in southern Caracas before climbing onto the red campaign truck that has been a prominent feature of his rallies.

“We’re going to give the bourgeoisie a historic lesson,” he said, as thousands of supporters cheered him on.

But with less than three weeks before the country’s crucial Oct. 7 vote, even a low-intensity Chavez is proving he can inflict serious damage.

In the last few weeks, Chavez opponent in the race, Henrique Capriles, 40, has had to face aggressive government supporters and almost daily accusations. The barrage began early this month, when a former ally produced a document that he said proved Capriles was bent on rolling out punishing economic reforms. The campaign denied the charges and said the papers were forgeries straight from the Chavez dirty-tricks machine. But it put Capriles on the defensive.

Days later, emboldened Chavez supporters forced Capriles to cancel an appearance in Caracas. They followed up by barring him from the airport in Puerto Cabello and burning one of his campaign trucks.

“It’s safe to say that the government has entered the negative phase of the campaign,” said Herbert Koeneke, a political science professor at Simon Bolivar University, who sees a hint of desperation in the acts. “I think it’s evidence that, within the government, there’s fear (of losing).”

The biggest blow to Capriles came last week, with the release of grainy video of Juan Carlos Caldera, one of his closest advisers, taking money from an anonymous donor and offering to set up a meeting with the candidate. Caldera said the money wasn’t intended for Capriles but his own mayoral bid, but the ruling PSUV party has called for an investigation suggesting Capriles is being backed by shadowy forces.

Capriles expelled Caldera from his coalition, but the incident has generated doubts in corruption-weary Venezuela.

While most polls give Chavez a comfortable lead, the opposition dismisses many of the studies as government propaganda. Even so, one of the most respected pollsters, Datanalisis, gives Chavez 46.8 percent of the vote versus Capriles’ 34.3 percent. The Datanalisis numbers have been widely reported in the local press, but the company will not confirm the proprietary information. Consultores 21, another closely watched pollster, however, predicts a much tighter race, giving Capriles a thin lead with 47.7 percent of the vote versus Chavez’s 45.9 percent.

A former tank commander, Chavez is used to rolling over rivals — not being forced into hand-to-hand combat. During the last election, in 2006, he won 62.8 percent of the vote versus Manuel Rosales’ 37 percent.

But this year is different. The president’s attempts to blame previous administrations for soaring crime, double-digit inflation and food shortages are ringing hollow after holding the top job since 1999.

In addition, Chavez entered this race as he was recovering from an undisclosed form of cancer. While he claims he has completely overcome the illness, his appearances are usually confined to television studios or podiums high above the crowd, which have many speculating that he’s watching his health as carefully as his campaign.