The use of marijuana as medicine is at odds with most laws in the United States. Possession, cultivation, and distribution of marijuana violate federal law. With various degrees of severity, all states have statues on their books that prohibit these activities. This is what made the passage of Proposition 215 by California voters in 1996 a milestone. Under Prop 215, marijuana activities that are illegal under Federal law – possession, cultivation, and distribution – are legal under state law providing that the patient has a physician’s recommendation. Eight other states – Alaska, Arizona, Colorado, Hawaii, Maine, Nevada, Oregon, and Washington – have followed with similar legislation, all by ballot initiative passed with wide majorities except for Hawaii where the change was by legislative action. In the past five years, 20% of the U.S. population has had a chance to vote on medical marijuana, with overwhelming majorities in favor of allowing medical use.

Because of its illegal status and reputation shaped by years of negative propaganda, marijuana has found itself at center stage in the "War on Drugs." This policy toward substance abuse is based in part on discouraging children from entering the gateway to more addictive and dangerous substances through marijuana. In 1999, the National Academy of Sciences Institute of Medicine’s Marijuana and Medicine: Assessing the Science Base not only dispelled the gateway theory but also gave credence to medical uses of the plant.

Thus, from 1996 onward, momentum has been building to legitimize marijuana as medicine. Survey after survey shows that favorable public opinion is growing. Failed legislation shows that lawmakers have a way to go. There may be consequences to this inaction.