NEARLY 7,000 FEET BELOW COCHABAMBA, reached by a rutted switchback highway that plunges through jungled canyons, lies Villa Tunari, the biggest town in the Chapare. Villa Tunari has been billed as the epicenter of the country's "eco-adventure-tourism industry," offering activities ranging from river rafting to birdwatching. But it's hard to promote ecotourism when the jungles are riddled with cocaine laboratories and the whole region has for years been the site of a bloody battle between coca growers and the U.S.-backed Bolivian antidrug forces.

A dozen or so near-empty eco-lodges littered the roadside, remnants of a tourist mecca that never fully realized its potential. Half a dozen bedraggled backpackers, both Europeans and Americans, wandered along the muddy main road or sat in ramshackle cafés sipping Coke Zero, a new diet soft drink that provides an inadvertent pun on the brutal Bolivian and U.S. coca-eradication policy that ended in 2002.

We stopped for lunch at an outdoor restaurant in the center of town. There were four of us now: Villalon, Abramson, me, and Fernando Salazar, a pudgy, affable social scientist from Cochabamba whom we hired as our translator and assistant. The place was deserted. Large, dusty jars filled with boa constrictors pickled in formaldehyde lined the counter in front, along with preserved wild-pig fetuses, lizards, and other rainforest oddities. "Charming," said Abramson. "Just the thing you want to look at over lunch." A young waiter shuffled over and slapped down a few grease-stained menus: The choices were wild pig, antelope, or some large river-bottom feeder grilled with clarified butter. No boa constrictor? I asked. He stared back, uncomprehending.

The grainy black-and-white television in the back of the café blared the local news. Teachers were on strike. Miners were threatening a strike. In La Paz, long lines of people waited through the night for cooking gas. The big story of the week was the hunger strike that passengers called after Bolivia's biggest airline, Lloyd Aereo Boliviano, allegedly went belly-up, leaving hundreds stranded at the country's airports. The camera panned across haggard families sleeping in front of abandoned check-in counters, surrounded by placards demanding intervention: COMPANERO EVO MORALES DOESN'T DEFEND US, one declared. HE IS ONLY FOR THE COCALEROS, BUT WE ARE ALSO BOLIVIANS!

About the only place in that somnolent burg where we found any activity was the soccer field, which Salazar took us to after lunch. We were looking for Rolando Pacheco, head of field operations for the Economic and Social Development Office in the Tropic of Cochabamba—the man responsible, at least before Morales came along, for locating and destroying coca plantations in the Chapare jungles. We found him—a chain-smoking tecnico, or coca eradicator, who looked to be in his early fifties—cheering on a bench at one end of the field, where two dozen mud-splattered young tecnicos were playing one of the most furious matches I've ever seen. I shook Pacheco's hand and jokingly asked him whether the tecnicos ever played teams of narcotraficantes or cocaleros. He cracked a sad-eyed smile.

Pacheco remembers the dark days after the 1980 military coup. Under that corrupt dictatorship, cocaine base was sold openly in town markets. One of the country's most powerful drug traffickers, Roberto Suarez, hired Klaus Barbie—former Gestapo chief of Lyon, who'd taken refuge in Bolivia after World War II—as his security consultant. They used soldiers and mercenaries such as Los Pajaros Negros ("the Blackbirds") and Los Novios de la Muerte ("the Fiancés of Death") to guard plantations and eliminate would-be competitors. "The army became filthy rich," I was told by one expert.

Then, in 1982, Bolivia flip-flopped. Massive street protests against the military resulted in the establishment of a civilian-led democratic government. The following year the U.S. helped to create UMOPAR ("Mobile Units for the Patrolling of Rural Areas"), a special police unit responsible for cocaine interdiction. In 1998, American-trained antidrug forces launched Plan Dignidad, otherwise known as "Coca Zero," which, by 2000, brought the country's total coca acreage down to about 36,000. The sweeps unified the coca federations in resistance, helping propel Morales to power.

In 2004, as the chief of the cocaleros' union, Morales forced President Carlos Mesa—who was unwilling to provoke further violence between the government and the cocaleros—to sign an agreement to allow roughly 8,000 acres for coca cultivation in the Chapare. The agreement also gave farming families in the region the right to own a cato, or a little less than half an acre, of the crop. Then, in his 2006 proposed law, Morales not only sought to up the legal acreage but to grant individual proprietors the right to divide their farms among immediate family members over age 18, each of whom could also grow a cato. After 25 years and hundreds of millions spent on eradication and alternative development, Salazar told me, "the U.S. managed to reduce the coca crop from 110,000 to 60,000 acres. In the end, the cocaleros won the fight."

After a few minutes of watching soccer, Pacheco led us into a back room in the tecnicos' compound down the road from the soccer field. Times have changed, said Pacheco: The powerful local federaciones—which dole out land to peasant farmers, collect taxes, market coca, and build schools—are supposed to make sure that everybody keeps to his legal limit. The new buzz phrase in Bolivia is "social control." But there's no way to guarantee that the farmers and federation leaders are behaving honestly. Pacheco pulled out a recent satellite map of the Department of Cochabamba, the province that includes the Chapare. It was covered with tiny green circles, each one representing a field of coca; there must've been thousands of them. "There is no control," Pacheco admitted. Earlier, Salazar had told us that Pacheco was depressed. He was watching his life's work go to hell. The sad-sack tecnico boss had been, in his day, one of the hardest anti-cocalero ideologues in the Chapare. Pacheco keeps his cards close to his vest, however. When I asked him how he felt about the coca reforms, he shrugged and replied, "It's not my place to get into politics."