Or, in the words of one farmer in Calvario: “There is no real order here. We are governed by narcos.”

Not that anyone in Calvario much cares for — or even knows — of the broader debate over the drug trade. Villagers see little harm in cultivating opium. No one here uses the drug, or its derivative heroin, and the day rate for labor in the poppy fields is many times what is paid for shucking corn.

Isolation breeds a certain detachment. Calvario, though just a few miles from the state capital, is marooned an hour’s drive up unpaved mountain switchbacks littered with boulders and ruts. In the village of around 100 people, there is limited awareness of the outside world. Some farmers are not entirely clear what opium is even used for.

José Luis García, a farmer in Calvario who leases his land for opium cultivation, asked more than once what exactly it was about poppies that drove Americans so crazy. After hearing of the epidemic of addiction in the United States, Mr. García paused for a moment to reflect on the ethics of growing poppies.

“The fault is not with those who cultivate the opium,” he said. “It’s with the idiots who consume it.”

For years, Mexico has operated as much more than just a transport hub for drugs bound for the United States. In addition to opium poppy, the cartels grow marijuana and manufacture methamphetamines, textbook examples of the backward and forward links that business students might encounter in their coursework. By both growing and distributing, the drug cartels can keep more of the profit.

For farmers living in remote Calvario, opium cultivation has a certain logic. It is a hardy plant, with two growing seasons that yield a modest harvest in the summer and a more substantial one in the winter. Getting goods to market is also simple: The traffickers come to them, driving their flashy trucks into the remote village outposts and buying directly from the farmers.