Marijuana is safer than aspirin, let alone alcohol and cigarettes. Having laws against it is like having laws against spinning around really fast until you get dizzy: it's idiotic and irrational. The only reason for it is because it gives the cops an excuse to harrass young people, blacks, the homeless, and nonconformists, and because the powerful tobacco corporations have the government on a leash.
Alcohol leads to cirrhosis, DTs, and acting like an ass; tobacco leads to emphysema, lung cancer, and inability to sit still for 10 minutes without a fix; marijuana leads to the munchies, creative inspiration, and worst of all, laughter. Wow, good thing the government is out there to save us against choices that are bad for our health! It would be awful if there were fewer people out there driving cars down the sidewalk and more giggling!
Not only should it be legal, every day it isn't is a crime against humanity and all good sense.
To misquote Timothy Leary, 'Weed causes panic and temporary insanity in people who do not smoke it.'