Greg Campbell, the author of Blood Diamonds, about the global trade in conflict diamonds, discusses the morality of pot use in an article in The New Republic:
Many smokers will point to the carnage south of the border as an argument for legalization. They’re right, of course, but legalization isn’t likely to happen anytime soon. In the meantime, the responsibility for ethical behavior falls squarely on the end-user—the casual marijuana smoker. When diamond customers learned that their purchases of rings and necklaces were inadvertently supporting a barbaric insurgency, they were outraged and changed their buying habits; some stopped buying diamonds altogether if they couldn’t be certain of the source. Marijuana users should adopt the same moral calculus.
In other words, if you can’t prove your pot is conflict-free, you shouldn’t be smoking it. The only people who face a genuine ethical dilemma are medical patients who find relief from debilitating illnesses with cannabis and who can only access it through the black market. Recreational smokers, though, have no such excuse. Buying marijuana for the purpose of getting stoned is a luxury. And when luxuries come with a cost that is measured in thousands of human lives, continuing to fund the killers is simply indefensible. That’s as true of pot as it is of diamonds.