Hemp, a strait-laced cousin of marijuana, is an ingredient in products from fabric and food to carpet backing and car door panels. Farmers in 30 countries grow it. But it is illegal to cultivate the plant in the United States without federal approval, to the frustration of Hauge and many boosters of North Dakota agriculture.
This is one of those places where the law is stupid. The history of it is at least partially tied up in racism, and partially in the wood paper business of William Randolf Hearst.
Hemp makes a better paper that wood. There is more cellulose in an acre of hemp than an acre of trees. And unlike trees, hemp can make fabrics as well as papers. Hearst owned a lot of forest, so you can guess that making hemp illegal along with marijuana would bring him into a fair bit more money than he already had. Writing about the "terrors" of stoned Mexican migrants was a win all around for him. He sold more newspapers with these fanatical stories, demonized the Mexicans who he hated, and got rid of a rival product.
So the original reason for the law banning hemp was not really in the best interest of the public, but rather one member of the public and his family. The biochemistry doesn't support the ban either. The main psychoactive component of marijuana is of course THC. I say main because the combustion of organic material is not neat. There are many things that burn and many things that change chemical activity at different temperatures. There might be more compounds present, but they probably have relatively low activities. That said, hemp wont get you stoned.
"You could smoke a joint the size of a telephone pole," Hague said of hemp, "and it's not going to provide you with a high."
The history and the biochemistry don't support the ban. That alone should be enough. Superfluous and stupid laws should be removed. There are also plenty of environmental reasons. Cellulose is a good starting point for biofuels, especially since it isn't a food crop and wont drive up the price of milk the way corn ethanol has. Its a dense crop and doesn't need much in the way of pesticides.
As is almost always the case with an illegal drug, I learned about the history of marijuana and hemp from Illegal Drugs by Paul Gahlinger.