Why is hemp illegal?

History of hemp laws
1619- First Hemp Law
A "must grow" law, any farmer living in America NOT growing hemp would be imprisoned or kicked out of the country.  At this time, hemp was one of the most widely used plants in the world.  In fact, the first two drafts of the Declaration of Independence were written on hemp paper.
1900- Mexican immigrants introduce the recreational use of marijuana.  Marijuana became associated with these Mexican immigrants.  Anyone who was prejudice against Mexicans also became a prejudice against marijuana.
1930- During the Great Depression, the public resented Mexican immigrants because of the huge unemployment rate.  Marijuana was associated with crime, violence, and social deviance.
1937- Laws Against Hemp
Marijuana Tax Act- Hemp has become criminalized.
1996- Legalized use in California.

For a more detailed timeline, visit this site. (10)

taken from norml.org/laws/hemp-2

Since 1996, several states have legalized marijuana for medicinal use:

Washington (Now completely legalized), Oregon, California, Nevada, Alaska, Arizona, Hawaii, New Mexico, Colorado (now completely legalized), Montana, Michigan, Massachusetts, Vermont, New Hampshire, Maine, Rhode Island, Connecticut, New Jersey, Delaware, Washington DC (12)

When hemp was criminalized in the 1930's, this set a reputation that has been hard to overcome until the recent years.  Marijuana is still believed by many to be a dangerous drug, which is hardly the case.

CEO's
In the United States, although we import hemp products the plant itself is illegal to grow.  Because of the widespread uses of the Cannabis sativa plants, you can imagine that this would hurt the profits of several industries.

-One huge industry, pharmaceuticals, would take a huge blow if growing hemp was legal.  Marijuana has shown to help treat many diseases and disorders (11):

Cancer- marijuana treats many side effects of the treatment for cancer, including nausea.  Also, some studies have shown that marijuana slows down the progression of cancer.

AIDS- marijuana helps with AIDS patients by reducing nausea and loss of appetite that the virus and medications cause

Multiple sclerosis- can relieve the muscle spasms, pain, and unsteadiness caused by the multiple sclerosis

Glaucoma- marijuana can relieve the eye pressure caused by glaucoma

Epilepsy- marijuana can prevent seizures

Anorexia- marijuana stimulates appetite, and reduces anxiety

Chronic Pain

Depression/Anxiety/Obsession- marijuana can stimulate your mind and elevate your mood

Because marijuana as a drug has so many widespread uses, the pharmaceutical companies would have significant sales drops if people were just able to grow their own medicine.

-Another industry, logging, would also have reduced demand if hemp was used for paper instead of trees.

Sources

10) "Marijuana Timeline" PBS. http://www.pbs.org/wgbh/pages/frontline/shows/dope/etc/cron.html

11) "Medical Marijuana for Pain and Depression" Disabled World Toward Tomorrow. http://www.disabled-world.com/medical/pharmaceutical/marijuana/

12) "State Laws" Norml: Working Towards Marijuana Reform, 2013. http://norml.org/laws/hemp-2