I am opposed to marijuana decriminalization.

So let's look at why Colby Cosh is in favor, and some of the reasons he cites for his position, and some of the bad reasons cited by others for my position.

First, I believe that there is no reasonable medical-use slippery slope that would lead to legalization. If there are useful medical uses -- something that's still being studied -- then there should be MJ-based prescription drugs. Or maybe prescription pot, if we can't figure out how to isolate the active ingredient. This doesn't require mass measures such as legalization or decriminalization any more than we need to legalize heroin to prescribe morphine.

In the immediate short term, when there are anecdotal but widely accepted claims of valid medical uses, the current protocol of minimal enforcement is a humane compromise. In the long run, the medical value claims will be proved or disproved, and prescriptions will be available appropriately to those who need them, and we can go back to strict enforcement.

Why shouldn't marijuana be legalized, Colby asks, when alcohol is legal? And I add, when tobacco is legal? Although alcohol is an intoxicant with dangerous side effects, no-one proposes restricting its sale or use. We've tried that, after all, and every reasonable person regards Prohibition as an abject failure. Although cigarettes pose severe health hazards and are highly addictive, no-one proposes banning them -- because the government is addicted to cigarette tax revenue. Instead, we are regulating legal public smoking areas out of existence.

Unlike alcohol, though, marijuana cannot be made in every house or shed from locally available materials (sugar, water, yeast). It's pretty easy to make beer -- I do it every couple of weeks. (With work eating my brain the last two weeks, I let myself run out of beer. Probably brewing later today.) It's pretty easy to set up a still and make the hard stuff -- I've done it in chem lab. Alcohol prohibition failed for these pragmatic reasons, in addition to failing the "it's my body" ideological test.

But legal pot falls down right here: it's not just your body. Pot is an intoxicant which, when smoked, poses serious health hazards. Furthermore, its secondhand smoke, unlike tobacco smoke, can be intoxicating. (Anecdotal reference only, sorry -- try searching google for contact high and see what you get: I find churches and counselors.) If public pot smoking can intoxicate innocent third parties, then it is unacceptable. If tiny amounts of alcohol intoxicate you, you can choose not to drink and you'll be fine. If tiny amounts of d9-THC intoxicate you, and you walk past a couple of stoners on Whyte, you're catching a cab home. That's the core problem here. That's why public pot use is a public harm, rather than neutral or good.

Then there's the cognitive effects. The editorial that Colby claims will help you "learn the facts" about cognitive impairment concludes:

In conclusion, currently available scientific evidence shows that almost certainly, some cognitive deficits persist for hours or days after acute intoxication with cannabis has subsided. The consensus across studies is strong enough to discount the likelihood that this finding can be explained by any combination of confounders. But whether these deficits increase with increasing years of cannabis exposure remains uncertain.

I read that as "smoking pot makes you stupider and we're not sure if it's cumulative." Excuse me, Dr. Pope, but DUH! We knew that one back in the dorms, only it was usually phrased differently. I clearly remember one guy (physics major), who was freaking out because he couldn't remember things related to his classes. When he sobered up, it didn't get better, because he couldn't remember what it was that getting baked made him unable to remember.

Maybe this can help explain why people who smoked pot as kids now prevent their kids from smoking pot. Maybe the keyword for their behavior is not hypocrisy but chagrin.

I wouldn't be against legal pot if I thought that it could be kept in private enclosed spaces among consenting adults, and if strict penalties -- like those related to alcohol intoxication -- should be applied to those who drive or operate heavy machinery while high. But I'm worried about slippery slopes, and conveniently, Eugene Volokh has a lovely paper explaining when a slippery slope is a valid concern.

In particular, I'm worried about the commercial free speech rights pot vendors will claim, after the Supreme Court makes mincemeat out of tobacco advertising restrictions. I certainly don't support full legalization, with billboards, pot smoking sections in restaurants, and the whole nine yards.

So I'll stay opposed to decriminalization, even though it's ideologically appealing. I'm not going to help push the rock halfway -- because I'm afraid that the rest of y'all will take it from there.