Change the law!

Cannabis sativa is a plant in the Cannabaceae family. It is known for its psychoactive effects, due to chemical compounds like THC.
Evidence of cannabis consumption has been found as far back as the 3rd millenium BC, associated to the Hindu religion, in India and Nepal.
In the 20th century, it was embraced by the Rastafari movement and it became illegal in most Western societies. There are many explanations to this: 1) economic interests of the paper and chemical industry; 2) beneficial effects of hemp would lower the profit of pharmaceutical companies; 3) racism directed to associate American immigrants of Mexican and African descent with cannabis abuse.
Today, recreational use drives a sizable demand for the drug, generating an estimated $36 billion market in the USA. Most of the money is spent not on growing and producing but on smuggling the supply to buyers.
The typical retail price in the streets of Portugal is 5€/gram, one euro bellow the median value in Europe.
Medical marijuana can be used in the treatment of conditions like glaucoma, cancer, AIDS, multiple sclerosis, chemotherapy-induced nausea, arterial blockages, clinical depression, anorexia, epilepsy, bipolar disorder, obsessive compulsive disorder, Tourette syndrom and Alzheimer's, but it is still a contorversial issue. (see http://en.wikipedia.org/wiki/Medical_cannabis)

Reasons in favor of legalization:
-money invested in restraining cannabis could be invested in another areas
-crime is committed to fund the traffic
-there would be more space in prisions
-adulterants in illegal cannabis can be very dangerous for the consumer

I think it should be legal. "The herb is the key to new understanding of the self, the universe, and God. It is the vehicle to cosmic consciousness"

Sources: wikipedia

add: I have just watched a documentary and I want to add a few things to this post.
Well, as you should know, THC, one of the chemical compounds found in cannabis, is believed by some people to have psychotic effects. Recent discoveries show that CBD, another of its compounds, has anti-psychotic effects...