The Christian Science Monitor recently published and article that was picked up on yahoo titled
"7 big myths about marijuana and legalization", which really should be called 7 illiberal arguments supporting the status quo. And by illiberal I mean not taking an indepth examination from many angles. Here is a point by point response.
1.Marijuana is not physically addictive, not matter how strong it is. And strength varies based on production methods. A push towards indoor grows has forces yields up in order to make it profitable to grow. In addition a greater medical usage as pushed this trend as well. You could get stuff in the 60's nearly as strong, it just wasn't as common. Additionally you can cut it so it's not as strong.
The study about IQ is about persistent use, a bad idea with any drug, and minors, who would likely find it harder to buy should it be legalized.
2. BS. Sativex does get you high. It contains THC as an active ingredient, and "The most common adverse effects in Phase III trials were dizziness (25%), drowsiness (8.2%) and disorientation (4%)" Sound high to me. Once medical marijuana passed in California, the use of over a dozen categories of pharmacueticals decreases, most notable opiates and other painkillers. With medical study and breeding programs you can tailor a for specific combinations of bio-active compounds, you you can extract and re-mix these components as desired (like what sativex does) and it's be a lot easier if cannabis were legal.
3. This is 0.3% too many, and how convenient that you leave out compound offenses, and distribution charges.
4. Prohibition did not decrease alcohol use. However since 1970 education and other measures has reduced per captita alcohol consumption by more than 20%. Rates of smoking have dropped from 40% to about 20%. Education, treatment, and harm reduction policies can do a lot to affect drug usage. Prohibition at best will shift drug usage from illegal to legal drugs.
5. The methodologies on many of these studies are suspect. They count only costs and not hidden benefits. For instance with smokers if you use total expected lifetime healthcare cost on the social dime it turns out to be a wash. While smoking does cause fatal and harmful diseases, their tendency to die much earlier than their peers, they are less likely to be treated on diseases of old age that are often very complex and expensive to treat. Also you're counting not just on revenue, but the decreased spending needed to keep up prohibition. With alcohol most drinker impose no social costs, they drink moderately, or socially and avoid operating heavy machinery under the influence. It is a small number of stupid people who use alcohol and impose enormous public costs. Lastly these costs are largely imposed by the discretion of the government to provide certain services. If we don't like a person's choices, maybe we should just stop subsidizing them.
While it's likely marijuana use is likely to increase as a result of legalization it's just as likely that alcohol consumption will see a corresponding decrease, likely lowering total social costs as marijuana impairs driving less and is not associated with violent behavior. I for one would be one making such a trade if marijuana were legal.
6. Portugal and the Netherlands provide successful models of DECRIMINALIZATION for all drugs.
You mention the treatment programs being ramped up, which is a great way to decrease social costs mentions in 5.
Decriminalization of all drugs in the minimum sane reform to U.S. drug policy. Legalization of marijuana rests on it's own merits.
7. You've contradicted yourself in the same article. You say on one hand current efforts are just and effective, and then you say use is a growing problem and cost.
This whole thing is premised on the idea that drug use is bad of undesirable. It's not. In moderation or for good reason drugs can and will improve lives. Problems from marijuana come mainly from overuse, it's illegal status, and use as too young an age.