Everyone in cannabis has heard the story: newspaper baron, chemical company, banking family, a plant banned to protect industrial interests. It is a good story and it is the reason many people first take an interest in this history. Most of it does not hold up against the documents. What actually happened is better documented, more ordinary, and in some ways worse.
This is United States legal history from 1937. It is not Thai law and has no application in Thailand, where cannabis flower is a controlled herb under the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568, dispensed on prescription form PT 33.
1. The Documented Record
The Marihuana Tax Act of 1937 is one of the better-documented pieces of American drug legislation, and the basic chronology is not in dispute.
| Bill | H.R. 6385, introduced 14 April 1937 by Rep. Robert L. Doughton (D-NC); hearings before the House Ways and Means Committee 27–30 April and 4 May 1937; revised as H.R. 6906 on 11 May 1937 |
| Drafted | In the Treasury Department (Office of General Counsel, Herman Oliphant); championed by Harry J. Anslinger, Federal Bureau of Narcotics (FBN) |
| Signed | 2 August 1937, by President Franklin D. Roosevelt |
| In force | 1 October 1937 |
| Mechanism | Registration plus annual occupational taxes on everyone in the trade ($24 for importers, manufacturers and compounders; $3 for dealers; $1 for producers; $1 for physicians and other practitioners) and a transfer tax of $1 per ounce to registered persons but $100 per ounce to unregistered persons. Violations carried up to $2,000 in fines and five years in prison |
| Overturned | Key provisions held unconstitutional in Leary v. United States, 395 U.S. 6 (1969), on Fifth Amendment self-incrimination grounds; repealed by the Comprehensive Drug Abuse Prevention and Control Act of 1970 |
The legislative device explains the Act’s odd shape. It was not a prohibition on its face. It was a tax and registration scheme, built so that complying with it was impractical or self-incriminating in practice. The occupational taxes and paperwork fell on every grower, dealer and doctor. Anyone outside the registered system faced a $100-per-ounce rate, which the Senate Finance Committee report openly described as a heavy tax aimed at illicit users. That design is why the Act eventually fell on Fifth Amendment grounds three decades later.
2. State-Level Precursors, 1911–1937
The federal Act came at the end of a quarter-century of state and local laws, not the beginning. The best-documented sequence is:
- Massachusetts, 1911: cannabis was added to a broader law restricting the sale of several drugs without a prescription.
- California, Maine, Wyoming and Indiana, 1913: the California provision was a low-profile amendment to the state poison laws, pushed by the State Board of Pharmacy. Historian Dale Gieringer links it to pharmacy and narcotics reform rather than to Mexican immigration.
- El Paso, 1914: a city ordinance, often called the first local ban (some accounts date its entry into force to 1915).
- Texas, 1919: the first statewide law, which added “marihuana” to a general narcotics statute.
So there was no single pattern. In the Southwest, Mexican migration after the 1910 Revolution is one documented driver: local press coverage and some local laws tied cannabis smoking to newly arrived communities. Elsewhere, early laws grew out of general drug and poison-law reform. Later press coverage also linked cannabis to New Orleans and to Black jazz musicians. These associations were well established locally by the time the FBN took up the issue in the 1930s, and historians such as Musto and Bonnie & Whitebread treat them as central to the federal campaign.
The word itself has a history. “Marihuana” (also spelled “mariguana”) is Mexican Spanish. Isaac Campos has shown that it appeared in English-language newspapers well before the 1930s. Its deeper origin is unsettled: a Nahuatl source has been proposed, and Chris Duvall argues for an African-language origin (Kimbundu mariamba). The “María Juana” story is generally regarded as folk etymology. What the record supports is that by the 1930s the word was used in contexts that associated the plant with Mexican immigrants, and that it was written into federal law. Whether officials chose it deliberately as a strategy is not documented.
Cannabis was already under international control before 1937. The 1925 Geneva International Opium Convention brought “Indian hemp” under control, largely at Egypt’s urging. The US position later fed into the 1961 Single Convention.
3. The AMA’s Opposition, Which Is Real and Is Usually Underplayed
Dr William Creighton Woodward, legislative counsel to the American Medical Association, testified against the bill on 4 May 1937. He argued that the claims made about marijuana addiction, violence and overdose were not substantiated by evidence presented to the committee, and that the law would burden medical use and future research.
Woodward also made a procedural complaint. He said the AMA had learned of the bill late and had not been consulted while it was being prepared. He also noted that it was framed around “marihuana”, a term that physicians did not readily connect with the Cannabis preparations in their own pharmacopoeia. His concern about research proved prescient: US cannabis research stayed heavily restricted for decades afterwards. His objections were overridden.
4. The Conspiracy Thesis, Item by Item
The version in cannabis literature is the Hearst–DuPont–Mellon thesis, popularised by Jack Herer in The Emperor Wears No Clothes (first edition 1985). It runs roughly like this:
- William Randolph Hearst had timber and newsprint interests that cheap hemp paper threatened.
- DuPont had just patented nylon and needed hemp fibre out of the way.
- Andrew Mellon was DuPont’s banker and Anslinger’s relative by marriage.
- A new mechanical decorticator was about to make hemp economical.
- Hearst’s papers ran a racist scare campaign, and the Act followed.
Here is where each element stands.
| Claim | Assessment |
|---|---|
| Hearst papers ran sensational anti-marijuana coverage | Supported. Even critics of the thesis accept that Hearst papers sensationalised marijuana crime, as much of the press did. A widely quoted headline, “Murder Weed Found Up and Down Coast” (said to date from January 1933), could not be traced to a specific paper and date, so treat that wording as unconfirmed |
| The term “marihuana” obscured the plant’s medical identity | Supported in effect. Woodward told the committee the AMA learned of the bill late, partly because of the unfamiliar name |
| The FBN had an institutional incentive | Supported. The FBN, created in 1930, faced Depression-era budget cuts and wanted a wider remit |
| The Act ended commercial hemp cultivation in the US | Overstated. Hemp was already in long decline before 1937, and the Act added a tax and registration burden. Production was revived in wartime from 1942 (see section 9) and declined again after the war |
| Hearst’s economic motive | Not supported. Hearst’s biographer W. A. Swanberg describes the chain as a net purchaser of newsprint, in debt to Canadian paper suppliers in the 1930s. Cheaper hemp paper would have cut his costs, not threatened him |
| DuPont needed hemp out of the way for nylon | Not supported. Wallace Carothers’ nylon patent applications were filed from 1935 (e.g. US 2,130,523, filed 2 January 1935) and granted in 1937–38 (both US 2,130,523 and US 2,130,948 were granted on 20 September 1938). No document links DuPont to drafting or lobbying for the Act. Nylon’s first major market was hosiery, where it competed mainly with silk, not hemp |
| The decorticator was about to transform hemp economics | Not supported as stated. George Schlichten’s machine from the 1910s never reached commercial-scale production before his death in 1923. The newer 1930s machines described in 1938 were commercially unproven (section 5) |
| Mellon | Family link to Anslinger: supported (Anslinger’s wife, Martha Denniston, was Mellon’s niece). Banking-motive link to the Act: no documentary evidence. Mellon had left the Treasury in 1932 |
| Popular Mechanics showed what was being lost | Not evidence of motive. The article appeared in February 1938, after the Act. Herer’s side says it was written in spring 1937, before passage. Even so, nothing shows that the bill’s drafters or backers read it, feared it or acted on it (section 5) |
The pattern is consistent. The parts of the thesis that hold up are about press sensationalism, terminology and bureaucratic incentive. The parts that fail are the industrial motives.
5. The February 1938 Popular Mechanics Article and Its Date
“New Billion-Dollar Crop,” Popular Mechanics, February 1938, is the most-cited document in hemp advocacy. It was a mass-circulation technology magazine, not an advocacy publication, which is what makes the piece useful evidence of how the industrial press saw hemp at the time.
What it says. The article claims that a newly available decorticator could separate fibre from stalk mechanically and make hemp economical. It says the woody residue is more than 77% cellulose and could feed more than 25,000 products, “from dynamite to Cellophane”. It cites a government estimate that 10,000 acres of hemp would yield as much paper as 40,000 acres of average pulp land. It predicts a crop worth several hundred million dollars a year to American farmers. It also raises the drug question directly: it notes that the female flower contains a narcotic and suggests that the concern was exaggerated.
The date question, fairly stated. The Act was signed on 2 August 1937 and came into force on 1 October 1937. The article appeared about six months later. Hemp advocates, Herer among them, answer that it was written in spring 1937, before passage, and printed late. That may be true. It still does not make the article evidence of motive:
- A forecast in a technology magazine is not proof that any newspaper owner, chemical company or legislator saw hemp as a threat. No document connects this article, or the machines it describes, to the people who drafted or pushed the bill.
- The article was not written in ignorance of regulation. It ends on the hope that “federal regulations can be drawn to protect the public without preventing the legitimate culture of hemp”. That reads as awareness of the new tax regime, not as a warning about a hidden plot.
What it is good evidence of: informed observers in 1937–38 still expected hemp to grow as an industrial crop.
What did not survive. The “25,000 products” figure is a claim about cellulose as a feedstock, and any cellulose source could serve. The paper comparison is a second-hand government estimate, not a yield study. The decorticators were commercially unproven when the article appeared. Wartime mills did process fibre at scale, but the industry did not survive peacetime competition. Cite the article as a contemporary record of industrial expectations, not as a technical authority or proof of suppression. It is short and worth reading in full.
6. What Historians Say Actually Drove It
The main scholarly account, from Musto and from Bonnie & Whitebread, attributes the Act to a mix of factors, none of them an industrial conspiracy:
- Racialised moral panic, particularly anti-Mexican and anti-Black sentiment. This had built up locally for two decades before 1937 (section 2) and is the element with the strongest documentary support.
- Bureau incentive. The FBN, created in 1930, faced Depression-era budget cuts and wanted a wider remit. Federal cannabis control gave it one.
- Genuine if misguided public-health concern, in an era with very little pharmacological understanding of the plant.
- Some accounts also point to moral-reform networks of the kind that had backed alcohol prohibition. Their role in the 1937 federal Act specifically is less well documented than the first three factors.
7. Why the Conspiracy Version Persists
Because it is more satisfying. A conspiracy has villains, motives and a moment of decision. The historical account has bureaucratic incentive, ambient racism, moral entrepreneurship and legislative inattention. That is how most bad law actually gets made, and it is much harder to tell as a story.
There is also a structural reason to resist it in cannabis writing. The conspiracy version makes testable claims, and the documentary record does not support its central ones. Each time someone repeats it and is corrected, the credibility of everything else in the field drops with it. The documented record is damning enough without additions:
- a Treasury bill championed by the bureau chief whose agency would enforce it;
- a medical association’s evidence-based objection overridden;
- a law that took thirty-two years to be found unconstitutional.
8. Two Things This Article Is Not
It is not a defence of the 1937 Act. By any modern standard the process was poor and the evidence base was worse. Woodward’s objections were well founded and were overridden.
It is not Thai law. Nothing in American legislative history has any bearing on what is permitted in Thailand. The operative instrument here is the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568. Under it, flower is dispensed only on prescription form PT 33, for no more than 30 days, with no refills, from a GACP-certified source, and it may not be sold or advertised online. Two Ministerial Regulations B.E. 2569 tightened licensing in 2026. The Cannabis Control Act is still a draft: the Cabinet approved it on 22 September 2026 and sent it to the House. See topic 1330 for the current position.
9. 1942: Hemp for Victory and the Wartime Reversal
Five years after the Act, the United States needed hemp again. Japan’s occupation of the Philippines cut off abacá (“Manila hemp”), the main fibre for marine cordage. The Act stayed in force. The government registered wartime growers under it and ran a production programme through the Commodity Credit Corporation and War Hemp Industries, Inc. Growers were paid for seed and fibre, and production peaked in 1943–44. The 1943 target was about 300,000 acres, against roughly 13,000 acres or less in previous years. Actual planted and harvested acreage was lower and varies by source. Two figures circulate in cannabis literature: “400,000 pounds of seed” and “42,000 tons of fibre a year”. These come from Herer’s book and are unverified.
To recruit farmers, the USDA made a short film, Hemp for Victory (1942). It is an ordinary agricultural extension film covering why the crop matters and how to grow, harvest and ret it. It is now in the public domain. Later enquirers were told by the USDA library and the Library of Congress that no such film existed. According to the commonly cited account, two VHS copies were donated to the Library of Congress on 19 May 1989 by Maria Farrow, Carl Packard and Jack Herer. The claim that the film was deliberately erased from official records is unsupported. Poor cataloguing explains the gap without a cover-up.
The episode supports the conclusion of section 6. As soon as the fibre was strategically necessary, the government worked around its own tax regime to grow it, which suggests the fibre was never the Act’s target. Production fell after the war. Abacá supplies resumed, synthetic fibres arrived in volume, and the guaranteed buyer disappeared. Without demand and processing capacity, the crop did not continue.
If you have read Herer’s account and found it persuasive, the most useful thing you could post here is which specific claim convinced you, and we can trace it to its source together. That exercise is worth more than any number of general warnings, and some of the claims do hold up, which is what makes it interesting.
Sources
- Taxation of Marihuana: Hearings before the Committee on Ways and Means, House of Representatives, 75th Congress, 1st Session, on H.R. 6385, 27–30 April and 4 May 1937 (includes the testimony of Dr William C. Woodward and H. J. Anslinger).
- US Senate, Committee on Finance, Report No. 900, 75th Congress (1937), on H.R. 6906: https://www.finance.senate.gov/imo/media/doc/75-900Rpt.pdf
- Leary v. United States, 395 U.S. 6 (1969).
- Richard J. Bonnie and Charles H. Whitebread II, The Marihuana Conviction: A History of Marihuana Prohibition in the United States (University Press of Virginia, 1974).
- David F. Musto, The American Disease: Origins of Narcotic Control (Yale University Press, 1973).
- Dale H. Gieringer, “The Forgotten Origins of Cannabis Prohibition in California”, Contemporary Drug Problems 26(2), 1999, pp. 237–288; revised version: The Origins of California's 1913 Cannabis Law - CaNorml.org
- Isaac Campos, Home Grown: Marijuana and the Origins of Mexico’s War on Drugs (University of North Carolina Press, 2012).
- Chris S. Duvall, The African Roots of Marijuana (Duke University Press, 2019).
- W. A. Swanberg, Citizen Hearst (Scribner, 1961).
- Jack Herer, The Emperor Wears No Clothes (first edition 1985): the source of the conspiracy thesis assessed above.
- “New Billion-Dollar Crop”, Popular Mechanics, February 1938.
- US Patents 2,130,523 and 2,130,948 (W. H. Carothers / E. I. du Pont de Nemours), Google Patents: US2130523A - Linear polyamides and their production - Google Patents ; US2130948A - Synthetic fiber - Google Patents
- USDA Economic Research Service, Industrial Hemp in the United States: Status and Market Potential (AGES-001E, 2000), section on the wartime programme.
- USDA, Hemp for Victory (film, 1942).
Educational article on US regulatory history. General information, not legal advice.