One thing I have found useful when talking to somebody who is blindly against legalization is to have good answers ready for all of the arguments for prohibition...
1) Marijuana is addictive.
I'd like to stop hearing pro-drugs people make the blanket statement that cannabis is not addictive. It's a proven fact that it's not physically addictive like alcohol or tobacco, but just like ANYTHING, cannabis can be psychologically addictive. I think that most people would agree that there are much bigger health threats associated with psychological addiction, especially in America (food -> obesity -> diabetes). Unfortunately, a lot of people won't understand this outside of our psychonautic community (which I am proud to say I just recently discovered and joined), but with a little bit of effort, respectful cannabis usage can steer past addiction and lead to amazing therapeutic qualities. The problem is that the majority of people use cannabis only for recreational purposes and have no clue what it is capable of.
2) Marijuana is a gateway drug.
This is actually true. But it's because drug dealers have other harder drugs they are trying to sell. How easy is it for some young impressionable kid to say "yeah sure, I'll try some coke/meth/heroin/etc. this time". On the other hand, if that person goes to the corner store to legally buy a pack of J's, the worse thing that will happen is that the clerk will try to push some alcohol on him (which, don't get me wrong, is almost as bad).
3) This is not your father's marijuana.
This one has always puzzled me. We keep hearing in the news about how unbelievably potent cannabis is getting (THC > 10% OMG!). That hydroponics in grow houses are causing the potency to spiral out of control. Hmmm... seems to me that if we REGULATED cannabis, the government could control this and use labels that advertise the THC content (hey, just like alcohol!). This would allow those of us with an IQ greater than 10 to adjust our intake. Not to mention having peace of mind, not needing to worry whether the Pb that the dealer put in my baggie to deceptively weigh it down is going to make me sick or send me to the hospital.
4) Marijuana causes violence and crime.
Outside of the unforgivable crime that a stoner may commit by flushing that allegedly cached herb that, in reality, he just packed seconds ago, the only crime associated with cannabis is related to the cartels. The real thinker here is... if we take away the cannabis market from them, are they all going to go get jobs at McDonald's, or are they going to find some other way to exploit Americans? Will the violence simply spread to the other illicit drug markets? I am not sure. But whatever the case, this violence has nothing to do with cannabis specifically. They say "guns don't kill people, people kill people". Well, as far as I'm concerned that little weed that helps make strong clothing and ease pain hasn't done anything wrong... it simply is the victim of a poor quality of human nature. Maybe society should concentrate on fixing that poor quality, instead of demonizing it's victim.
5) Taxing marijuana will NOT help the economy (well, Obama did actually say these words recently)
Huh? Schwarzenegger is currently trying to figure out how many thousands of teachers he needs to hand a pink slip to prevent his state from bringing down the rest of America's state economies. 56% of Californians are in favor of legalization (not just decriminalization, but full legalization, regulation, and taxation). What more do you need here? I think the governor is doing the right thing by cautiously moving ahead with a comprehensive study on the matter. I sincerely hope that this happens objectively, thoroughly, and quickly.
What others am I forgetting?