03/15/2012 01:43 pm ET Updated May 15, 2012

Alcohol, Marijuana and Murder

If it is true, as the Associated Press is suggesting, that alcohol may have been a factor in last weekend's slaughter in Afghanistan it would reinforce a formula known to every cop in the country: booze + triggering condition = violence. The "triggers"? Anger, of course, and its causes: jealousy, insecurity, stress (caused, perhaps, by repeated tours of duty), mental illness, racism, xenophobia... the list is endless.

What cops also know is that people under the influence of cannabis are rarely violent. In fact, in my continuing "research," involving the casual questioning of police officers throughout the land, I've not met one cop who has ever had to fight a person under the influence of marijuana, and marijuana alone. Alcohol, on the other hand? Let's just say my cops in Seattle would much rather have worked Hempfest than Mardi Gras.

Clichés about mellow pot smokers abound, but the research supports a solidly scientific distinction between the effects of marijuana and those of alcohol on violent or otherwise unsafe behavior. Millions of responsible adults have switched from beer, wine, or distilled spirits to marijuana, and done so for reasons of personal health and safety.

I'm not suggesting soldiers be furnished joints or fed green brownies. On the contrary, whether one agrees with a complete ban on alcohol consumption (or even possession) in war zones, it is imperative that soldiers, as well as cops, firefighters, pilots, and others, be "drug free" when on the job.

We'll know soon enough whether the U.S. Army staff sergeant accused of murdering at least 16 Afghan civilians was under the influence of alcohol.

If so, we have further justification for concluding that a prohibited substance, marijuana, is far, far safer than a permitted one, alcohol.