Not the federal government's business.
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people. -- The Tenth Amendment
Two chronically ill Californians (Angel Raich, 39, and Diane Monson, 47) are arguing before the Supreme Court that federal marijuana laws should not prevent them from using marijuana to calm the symptoms of their illnesses. Raich "suffers from an inoperable brain tumor and a host of other ailments" while Monson is afflicted with extreme back spasms. Both contend that marijuana is the only drug that relieves their suffering.
California voters approved a statewide referendum in 1996 to allow doctors to "recommend" marijuana to their patients to treat a variety of illnesses. The federal Drug Enforcement Administration has maintained that it will enforce federal drug laws in spite of the California law.
Arizona voters also passed a statewide referendum in 1996, which allows doctors to "prescribe" marijuana. However, the Arizona law is much tighter than the California law, so even if the Supreme Court agreed with Raich and Monson it may not open the door to medical marijuana in Arizona.
Supreme Court justices have expressed concern that allowing the use of medical marijuana could lead to increased recreational use of the drug, and that the drug could be obtained on the black market where quality is not assured. The problem with the first argument is that many drugs used for medicinal purposes (in addition to household chemicals) can be used to get a "high". Oxycontin, for example, is known as "hillbilly heroin" for the high it produces when crushed and either snorted or injected.
As to the second argument, marijuana can be grown in a controlled, regulated atmosphere where you do not have the quality concerns or the contribution to organized crime. Monson, for example, had a marijuana garden, but it was raided by federal agents.
There is little doubt in my mind that many advocates of medical marijuana are using it as a "Trojan horse" to move forward with complete decriminalization of marijuana, while others see medical marijuana as a "slippery slope" to decriminalization and oppose it for that reason. Both groups are playing politics with the health and lives of chronically ill people and should focus only on the benefits and drawbacks of medical marijuana itself.
The problem with medical marijuana is that marijuana (especially in smoked form) has serious health consequences. It impairs learning and memory functions, and smoked marijuana is carcinogenic, like tobacco smoke. (See here, here, and here.) Because of the negative health effects of marijuana, it is arguable that marijuana should be a "last resort" drug for treating sick people.
The lynchpin to this case is the Tenth Amendment, which is quoted at the top of this article. Why is it that a constitutional amendment was required to ban the sale of "intoxicating liquors", but no constitutional amendment is required for a federal ban on marijuana?
Drug policy should be left to the states, not the federal government. This became apparent during Prohibition, when the attempt to ban alcohol failed in the same way that the "War on Drugs" has failed. I have serious doubts that the framers of the Constitution envisioned the federal government setting drug policy (especially as it relates to medicinal use of drugs) to the states. While it is reasonable under the "interstate commerce" clause that the federal government regulate drugs for safety reasons, any outright bans should be a state matter. It can be safely assumed that all of the states would ban drugs like heroin anyway. The states are more than capable of regulating drug policy on their own.