The following excerpt from Home Grown: Marijuana and the Origins of Mexico's War on Drugs, by Isaac Campos. It is a summary the author's thesis at the University of Cincinnati, first printed as the introduction to Home Grown. (University of North Carolina Press, Chapel Hill, 2012).

The Conventional Wisdom is that marijuana prohibition was first imposed early in the 20th century by sheriffs in southwestern states seeking to increase their power over Mexican immigrants who had brought the herb from south of the border, where smoking it was part of the culture, no big deal. Then, the Conventional Wisdom continues, Hearst newspapers and Harry Anslinger’s Federal Bureau of Narcotics concocted and publicized stories of marijuana use causing violence and insanity, which led to Congress imposing a federal ban in 1937.

Around the year 1530, a conquistador named Pedro Quadrado left his small village near Seville and traveled to the New World. After actively participating in the ongoing conquest of Mexico, Quadrado received a coveted encomienda, or royal tribute and labor grant, to undertake the cultivation of cannabis there. He thus became the first person to cultivate this species in the Americas.

That, anyway, is what he himself claimed, and probably with justification, for it was not until June 1545 that the Spanish Crown first ordered its subjects to sow cannabis in the New World.

For the Spanish, cannabis was first and foremost a fiber plant. They called it cÃ¡Ã±amo. Tall, green, and gangly, of round seeds and “abominable smell,” this was an extraordinarily common cultivar whose strong fibers, or hemp, made clothing, rope, and the broad and sturdy sails that powered the greatest sea-borne empire the world had ever known. Thus began the long journey of cannabis through Mexican history, one that would eventually see its meaning and identity radically transformed.

The first signs of that transformation appeared in the 1770s. By then, cannabis had found its way into local medical-religious practice, and its seeds and leaves were sold by herb dealers under the name pipiltzintzintlis, or “the most noble princes.”

Though still cherished by Spanish officials as an industrial fiber, there were growing rumors that, for Indians, it also facilitated visions, communion with the devil, and sometimes madness. Prohibitionist edicts briefly raised the profile of these noble princes, but the name pipiltzintzintlis would soon fade into obscurity, as would (temporarily) the drug use of cannabis in Mexico.

A new generation of nationalist botanists would rediscover cannabis drugs during the 1850s. These men become interested in cataloging Mexico’s “indigenous” natural wonders, and in the process they noted that “certain Mexicans” had begun smoking the stuff. The word pipiltzintzintlis was no longer in use, but two other local designations, both of which helped to reinforce the plant’s apparent indigeneity, had emerged: rosa marÃ­a and mariguana.

The former would also soon disappear, leaving the word mariguana, or marihuana—or as it is now spelled in English, “marijuana”—to conquer the lexica of most of the Western Hemisphere.

Though these nationalist botanists saw potential value in this “local” drug plant, their writings would soon be overwhelmed by the view that this was a quintessentially indigenous “narcotic” causing madness, violence, and mayhem. In 1886, for example, a Mexican medical student delivered a thesis in the field of legal medicine on marijuana and the insanity defense, concluding that “the criminal responsibility of an individual in a state of acute marijuana intoxication should be exactly the same as that of the maniac,” namely none.

By 1898, Mexico City’s leading daily could claim that “for years the press has described horrifying crimes, criminal eccentricities and suicides, which place before the court of public opinion individuals whose type oscillates between furious madmen and criminals worthy of being placed before the firing squad, and one after another case demonstrates that the murderer, the rapist, the insubordinate, the presumed suicide, and the scandalous acted under the influence of marihuana.”

During the late nineteenth and early twentieth centuries, hundreds of newspaper stories described marijuana’s effects in similar fashion.

Descriptions like this one of marijuana’s effects not only were standard during the late 19th and early 20th centuries but also went virtually unchallenged. As I demonstrate in chapter four, a close analysis of more than 400 Mexican newspaper articles —drawn from over a dozen publications, both liberal and conservative, and all describing the effects of marijuana— reveals that not a single article questioned this basic stereotype.

Given that these papers were published in an environment of significant media competition and that they routinely lambasted each other for untruths and sensationalism, this unblemished record is quite extraordinary. Furthermore, there is evidence that lower-class Mexicans, most of whom were illiterate, were equally convinced of marijuana’s frightening effects. As one commentator revealed in 1908: “The horror that this plant inspires has reached such an extreme that when the common people . . . see even just a single plant, they feel as if in the presence of a demonic spirit. Women and children run frightened and they make the sign of the cross simply upon hearing its name.”

In 1920, after labeling marijuana a threat to “degenerate the race,” Mexican sanitary authorities banned the drug nationwide, 17 years prior to similar legislation in the United States.

Originally an industrial fiber symbolizing European imperial expansion, cannabis had been transformed by the dawn of the twentieth century into a quintessentially indigenous, and putatively dangerous, Mexican drug plant. Thus, in 1920, after labeling marijuana a threat to “degenerate the race,” Mexican sanitary authorities banned the drug nationwide, 17 years prior to similar legislation in the United States.

For those readers familiar with the existing historical and social scientific scholarship on drugs in North America, much of this may come as a surprise. The War on Drugs is routinely described as “America’s War on Drugs” and the drug problem as an “American disease,” where “America” means the United States and the rest of the Americas have been cajoled or forced into cooperating.

Global drug prohibition has recently been portrayed as a kind of “informal American cultural colonization,” while Latin America has been identified as a place where, prior to U.S. involvement, substances like marijuana and peyote were an accepted part of “Indian and Latin American culture.”

The problem is not that historians have looked deeply at the origins of drug prohibition in Latin America and gotten it all wrong. The problem is that historians simply have not looked deeply at the origins of drug prohibition in Latin America.

Not a single monograph exists, for example, on the birth of these policies in Mexico. This is a remarkable fact given the tremendous political, social, and economic costs that the War on Drugs have produced in that country over the last century. Drug prohibition is the sine qua non of the War on Drugs. Without prohibition, there is no black market, and without a black market, there are no “narcotraffickers” to demonize, no illicit drug users to incarcerate, and no national security threat to declare.

Scholars who date the War on Drugs to Richard Nixon’s formal declaration of that “war” in 1971, or to the Reagan-era militarization of the conflict, are missing the forest for the trees.

That is why scholars who date the War on Drugs to Richard Nixon’s formal declaration of that “war” in 1971, or to the Reagan-era militarization of the conflict, are missing the forest for the trees. Nixon merely intensified an antidrug crusade that formally began at the federal level in the United States (and Mexico) in the early 20th century.

Certainly that “war” became more militarized in the late 1980s, but neither was this completely new. Mexico’s military, for example, had been eradicating drugs intended for the U.S. market since the late 1930s. In sum, the origins of the War on Drugs lie in the legal and ideological roots of prohibition. With respect to marijuana in North America, those origins have their deepest roots in Mexico.

Marijuana also provides a simply fascinating case study for U.S.-based historians interested in the ideological foundations of drug prohibition. It is a substance whose inclusion among “Schedule 1” drugs in the United States is often cited as a fanatical excess of extremist drug warriors, an unscientific designation proving that politics, not rationality, drives the War on Drugs. It is a compelling argument. After all, there is not a single death on record that can be attributed to overindulgence in marijuana, while serious research has long demonstrated that alcohol and tobacco are generally more habit-forming and unhealthy for their users than is cannabis.

Yet despite today’s typical view of marijuana as a “soft” drug in comparison to, say, the opiates and cocaine, Mexicans of a century ago believed it to be perhaps the “hardest” drug of them all, one that triggered sudden paroxysms of delirious violence. Could marijuana really have produced these effects?

And, whatever the answer, what was it about the historical circumstances of the day that made such descriptions so eminently believable? How is it possible that not a single newspaper or scientific source seriously challenged their veracity?

Finally, how did the radical transformation of cannabis’s meaning occur in Mexico between the sixteenth and twentieth century? Where in the plant’s long journey through Mexican history did these changes occur?

These are the questions around which this book is organized. By answering them, I hope to better explain marijuana’s prohibition in Mexico, itself a key to understanding the origins of the War on Drugs in that country and, to a certain extent, in North America as a whole.

Ultimately, the evidence will demonstrate that marijuana prohibition can only be described as a kind of “informal American cultural colonization” if one takes the radical step of considering Mexico as worthy of the “America” label as its powerful neighbor, for in this case the influence mostly flowed northward. Marijuana’s prohibition in Mexico was, in short, home grown.

Reprinted with permission from University of North Carolina Press, Chapel Hill, 2012.