-- Coca was king for years here in Bolivia's steaming Chapare jungle.

From the 1970s on, the leaf used to make cocaine brought thousands of peasants to this tropical basin 200 miles southeast of La Paz in the shadow of the Andes. Their crops vaulted Bolivia to the rank of the world's second-largest producer of raw and partially processed coca, making the country a hub of the regional drug trade.

But U.S.-supported Bolivian soldiers and military police last month completed an extraordinarily aggressive -- and successful -- three-year campaign to eradicate coca in the Chapare. As a result, Bolivia has fallen off the list of major drug-producing countries for the first time in almost a half-century. U.S. and Bolivian officials are calling what happened here the largest victory in the drug war so far, a model for other countries.

"Bolivia has done in the past two to three years what no other country has done in the drug war in Latin America," said Manuel Rocha, the U.S. ambassador to Bolivia. "In Latin America, this is the success story."

After years of failure -- including hundreds of thousands of U.S. tax dollars spent on disastrous attempts to pay farmers to stop growing coca in the 1990s -- victory was achieved mainly by toughening a program used to persuade poor farmers to switch to alternative crops.

Under the banner of President Hugo Banzer's "Dignity Plan," Bolivian soldiers fanned out over a region larger than Connecticut, tearing out coca plants from the tiny farms of an estimated 40,000 families. Unlike parallel programs in Peru and Colombia, where U.S. and government officials have tried to woo farmers to switch to legal crops voluntarily, farmers here got no choice. The U.S.-financed Bolivian troops simply stormed farms and uprooted coca leaf by force.

Their no-holds-barred strategy brought dramatic reductions, from 74,360 acres of illegal coca before the Dignity Plan rolled out in 1998 to roughly 6,600 acres today. Most of that is being grown in the distant Yungas lowlands, where an additional 24,000 acres are still planted legally for traditional indigenous uses such as chewing to fend off hunger pangs and for herbal tea.

While counter-drug officials herald the success in Bolivia, critics point out that the gains have been moderated by the growth of coca cultivation in other countries, such as Colombia. This has led some analysts to suggest that overall coca cultivation has shifted, not fallen.

The program here has also generated a profound economic shock for thousands of poor families in the Chapare who, according to local Roman Catholic Church and human rights officials, face malnutrition from the sudden loss of their livelihoods and limited attempts to help them switch to legal crops. Their plight has led some farmers to begin replanting coca, endangering Bolivia's gains.

"Coca was taken away and the farmers were abandoned -- this is not a battle won. It is a human tragedy for thousands of poor families with no way to support themselves now," said the Rev. Sperandio Ravasio Martinelly, pastor of Villa Tunari parish, one of the Chapare's largest.

Resentment among Chapare farmers has exploded into violence. A dozen peasants and soldiers have been killed in the past year in clashes that culminated in a blockade of the region by coca farmers in September. Now, with the government mounting a final offensive to close the last of the small coca markets in the Chapare and strengthen its grip through U.S.-funded training and upgrades at military installations, farmers and their leaders are organizing into small armed bands.

"We are not going to stop growing coca," said Congressman Evo Morales, leader of the Federation of Coca Growers. "And we will defend ourselves from this government, which has decided to blindly obey the orders of Washington with no thought given to its own citizens."

In a town called Paradise, 35 miles from the Chimore military base that has been the primary staging ground for Bolivia's Dignity Plan, a muddy path lined with sodden wood planks leads to the Mamani family.

Near the wooden hut that Silverio Mamani, 35, built 10 years ago on money made from coca, his wife, Mercedes Rios, has just slaughtered one of the family's last chickens, hanging the freshly cut flesh on a clothesline for drying into jerky. Their two last bony chickens move around, pecking at lustrous green Amazon grasshoppers too fast to be food.

"We have tried to spare the chickens for the eggs," she said, cradling one of their three children, "but we can't wait anymore. We need the food."

Like so many coca farmers, the couple moved here from the old Potosi mining region a decade ago, destitute after floods ruined their small farm in the Bolivian highlands. They had heard of a better life growing coca here.

At first, the rumors proved true. The family made about $800 a year during peak harvests in the mid-1990s, when Mamani cultivated 1 1/2 acres of coca. That income is 2 1/2 times what the government says the average Bolivian farmer makes. The family went from destitute to just poor, from potatoes and rice to chicken and the occasional omelet.

Then the soldiers came.

It was a blisteringly hot morning in June 1998. A convoy of military trucks surrounded Paradise. Armed soldiers piled out, forming a human chain to block wailing peasants who watched as their coca was yanked from the ground.

"I was crying, my children were crying -- coca was all we had," Rios said.

Six months later, the family received 6,000 pineapple plants from a government alternative development project. But Mamani, like many other farmers in a region where officials say there is roughly one technician per 300 families, said he received virtually no assistance on how to cultivate the plants.

Only half the pineapples bloomed. The rest, now rotting on his 13-acre farm, were attacked by a jungle fungus. Of the plants that yielded fruit, most were small and ill-formed. He was forced to sell them for a few pennies each. "We are eating rice and potatoes again, splitting food meant for two into six portions," he said.

Prices for many crops involved in the alternative development programs have fallen because of overproduction, poor quality, changing market conditions and limited access to buyers at home and abroad.

Bolivian government and other officials concede that alternative development has not kept pace with eradication. The U.N. Office for Drug Control and Crime Prevention says that only one-quarter to one-half of families here have received alternative crop assistance.

Bolivia's new agriculture minister, Hugo Carvajal, blamed the limited success on a lack of funds and a lack of skill by the Chapare's coca farmers to cultivate other, more demanding crops. But he also said that when he inherited the ministry late last year, it was overwhelmed.

The government's greater priority, officials say, is the poverty-stricken nation at large, which has suffered from an image as a drug haven, limiting access to international loans and steering away desperately needed foreign investment.

"Look, Bolivia is a poor country, and for years, the coca growers in the Chapare had a lifestyle much better than the average farmer in the highlands because they were growing an illegal crop," Vice President Jorge Quiroga Ramirez said in an interview. "Now, if I go to the United States and tell a bank robber that he has to stop robbing banks and get a legal job, should he expect to make the same amount he was making when he was robbing banks? I don't think so, and the coca growers must begin to understand that."

Quiroga also points to some coca farmers who have succeeded in alternative development as examples of what Bolivia hopes to achieve in the long term.

Rosemary Pozo, 36, is part of a community that promised to abandon coca, making it eligible for significant assistance from the U.S. Agency for International Development and the Bolivian government. Women in the community were brought together and taught to make tropical fruit jams out of new citrus crops. The jars now sell for about 75 cents each, earning Pozo's family roughly half the $1,700 a year it made growing coca.

"But it is enough for us to eat, and, more importantly, it has given us peace of mind," she said.

The government and the coca growers have traded accusations of torture and human rights violations during the eradication campaign.

Godofredo Reinicke, Bolivia's human rights ombudsman for the Chapare region, said the government has largely ignored allegations that U.S.-funded Bolivian soldiers have burned down homes, stolen food and possessions and tortured coca growers in search of intelligence for the Dignity Plan. He said he was shot at by the military two weeks ago while investigating a torture allegation.

"They have turned a deaf ear to the cruelty -- they just don't want to hear it," he said. "They have one thing on their minds, getting rid of coca. At any cost."

Lt. Col. Hernan Caprirolo, commander of Bolivia's eradication efforts at the Chimore base, bristles at the suggestion, saying his troops have been the target of snipers, booby traps and kidnappings by coca growers and drug traffickers. "We are the ones who are being killed in the line of duty," he said.

U.S. and Bolivian officials contend that a strong military hand in the eradication campaign was the key to -- not the cost of -- success.

"We tried other ways. We were handing over up to $2,500 to coca growers in the 1990s to have them switch to other crops, but what did they do? They turned around, spent the money, and then started growing coca again," Quiroga said. "The only thing we succeeded in doing was making coca the only subsidized crop in Bolivia. . . . So we made a political decision that the time had come to take serious action for the good of our country, not just for the good of a few thousand families."

Farmers toss coca leaves at a demonstration in Chimore, a primary staging ground for Bolivia's anti-drug efforts.