By JUAN FORERO

MOQUEGUA, Peru, March 28 — In a presidential campaign filled with symbolism, the front-runner here found a perfect image for his hard-charging crusade: on Tuesday, he jumped on a chestnut mare and, with his followers sprinting behind him, galloped to the central plaza to promise to revolutionize this Andean country.

The candidate is Ollanta Humala, 43, who was seeking to evoke the image of the authoritarian man on horseback known as the caudillo. He says that if elected on April 9, he will waste no time before cracking down on the multinationals he says cheat citizens and arresting the crooked politicians he says have plundered Peru. As the leader of the newly formed Nationalist Party, he also says he will ally himself with President Hugo Chávez of Venezuela, who wants to form a bulwark against the Bush administration.

Mr. Humala, whose first name means "warrior who sees all," is as populist as they come on a continent that has been swept by leftist leaders mining popular discontent with free-market policies and suspicions of the United States. His antiglobalization stance and talk of transforming the economy provoke fear in the entrepreneurial class; the stock market suffered its biggest tumble in five years when he rose in the polls.

But his message — Peruvians first — is compelling to many in this country of 27 million.

"We nationalists are going to found a new country," said Mr. Humala, a wiry man with close-cropped hair who campaigns in a red T-shirt that says "Love for Peru."

"Who is afraid of change?" he said. "Are the people afraid of change? No! Those who are afraid are the ones in power because they know if the nationalists get to power, Peru will change."

It is a simple, scripted message from which he rarely deviates, repeating it to reporters and his growing following, with little elaboration. The polls show it is working. His approval rating, 11 percent in November, has grown to 33 percent, putting him ahead of Lourdes Flores, a former member of Congress who stands at 27 percent, and Alan García, a former president whose administration from 1985 to 1990 left Peru a shambles, now at 22 percent.

Mr. Humala says he hopes that voters in Andean villages, where his support is strong, will help give him more than 50 percent of the votes so he can avoid a runoff.

"He's with the people," said Victor Herrera, 40, who was among the thousands who followed Mr. Humala on his recent swing through this arid desert in southern Peru. "He's not like the other candidates, who are with the big businessmen."

Though Mr. Humala wants to be thought of as another in a long line of leftist leaders to surge in Latin America, his background is a far cry from that of President Evo Morales of Bolivia, President Luiz Inácio Lula da Silva of Brazil or Mr. Chávez, who all grew up poor and spent years building social movements.

Rather, he attended an elite private school in Lima, served in the army, which has been criticized for widespread rights abuses, and studied in France.

Mr. Humala's father, Isaac, founded an ultranationalist movement, etnocacerismo, named after a 19th-century military hero. It speaks of the superiority of the Indian race over those descended from the Spanish, advocates revenge by Indians and mixed-blood Peruvians against the descendants of the Spanish and includes ideas like sentencing corrupt officials to death and closing the borders.

His mother said homosexuals should be shot so "there is not so much immorality in the streets." A brother, Antauro, a former army officer, led an attack by 150 army reservists on a police station last year, killing four officers. He was demanding the resignation of President Alejandro Toledo. A thousand soldiers retook the station and arrested Antauro, who remains in custody. Another brother, Ulises, considered by the family to be the standard bearer for etnocacerismo, is also running for president as a candidate of a fringe party, leading to a split with Ollanta.

Mr. Humala was part of his father's movement, and he and Antauro led a military uprising in 2000 during the last days of President Alberto Fujimori's quasi-dictatorship. "It's very hard to decide where Antauro ends and Ollanta begins," said Cynthia McClintock, a Peru specialist at George Washington University. "Humala was clearly once in that movement, and the overtones of racism and militarism are certainly very worrisome to people who think of themselves as on the left."

But in an interview, Mr. Humala said he had distanced himself from his relatives. "They are free to express ideas, but I reject them," he said. "My family is the people. The Humalas come second."

As he bounds across a stage like a talk show host, declaring his love for Peru, he comes across as a fierce nationalist ready to battle the affluent and anyone who opposes him.

He offers little detail about his plans, though he pledges to "build an alternative model to this neo-liberal model." The economy may have grown an average of 5 percent a year since Mr. Toledo took office in 2001, but economists say it has failed to produce prosperity for average Peruvians, leaving many discontent and searching for another path.

"The economic model is finished, it hasn't been the country's economic needs," Mr. Humala said. "There's been growth, but no development."

He accuses the multinational mining companies that drive the economy of having obtained sweetheart contracts, and he promises to squeeze them. He has criticized Peru's free trade agreement with the United States, suggesting that he would scrap it. And he says he would rewrite the Constitution, which he says favors foreign capital. Instead, he said, he wanted the government to get involved in some private projects, like the Camisea natural gas development.

Such talk worries the private business sector. "If he wins the election, I would predict a certain amount of capital flight and a fall in the stock market," said Fritz Du Bois, director of the Peruvian Economic Institute, a free-market policy analysis group.

Mr. Humala, however, relishes the conflict with industry, saying, "Our motherland is not for sale." Still, he is not seen by everyone as the selfless man of the people he paints himself to be. His credibility has been challenged by some of the same people he professes to represent — the highland Indians who suffered most in Peru's war with the fanatical Shining Path rebel group.

In the interview, Mr. Humala laughed nervously when asked about accusations that he killed peasants in the early 1990's when he commanded an army base in the conflict-torn Upper Huallaga Valley. A handful of families have filed criminal complaints against Mr. Humala, saying he committed atrocities, from "disappearing" their relatives to torture.

Mr. Humala, who retired from the army in 2004 as a lieutenant colonel, calls the allegations part of a smear campaign sponsored by rivals and "the elitist sectors who handle human rights themes."

"I have not violated human rights," he said. "This is coming out in the context of Ollanta Humala being the No. 1 candidate nationally."

Indeed, Mr. Humala's popularity has not been hurt by the accusations, prompting Mario Vargas Llosa, Peru's most famous author, to question the direction of the country's politics. "What is happening in the country for such political, moral and cultural blindness to take hold?" Mr. Vargas Llosa, who lives in Spain, said on a recent trip to Peru. "Maintain democracy or go to dictatorship: that is what is at play in these elections."

A recent United Nations study of Peruvian opinions found that 73.5 percent of respondents believed that the country needed an authoritarian government. Mr. Humala seems to offer that kind of leadership.

"We've lost our morals, and Ollanta, with his army background, is the right person for the job," said Francisco Carvajal, 50, a laborer in Ilo, another campaign stop. "I'd like to see him as president. The ones we've had have been liars and thieves."