Far be it from me to disrespect my Elder, but half his argument rubs me the wrong way — and it's the more important half. While I agree that financial concerns are a bogus excuse for legalizing pot, I'm still very much for legalization.
Now, I'm no pothead. I've tried the ganja, and it doesn't do much for me other than making me sleepy and even nerdier than usual. But I've also seen plenty of people smoke it often with no ill effects, and I can see the appeal. Yes, I've seen it abused; I've seen it be a partial (and I emphasize partial) contributing factor for someone dropping out of college. But a person should generally be allowed, though discouraged, to throw their life away. Besides, in the vast majority of cases, the only side effect of pot is that someone has a fun time.
I'm not Scalia; I don't hide ugly realities behind cold and unrealistic theories. Marijuana can cause problems, and the government should look out for people and give them every opportunity to sidestep addiction. It should finance this by taxing marijuana sales. But at the end of the day, lots of things can end up in suffering: alcohol, cars, marriage, skiing trips — almost everything can end badly, not just for the user but for innocent bystanders. The only way to end all human suffering is to carpet bomb the planet and ensure that there are no humans left.
Whenever the government restricts an action, the onus is on it to show that the wrongness of squashing a person's individual freedom is outweighed by the good of society. Lest I be painted as a libertarian, I'll emphasis that this greater good does often win out. Taxes, murder laws and speed limits are all good examples. I just haven't seen a good argument for why pot is worse than any number of fun things that can end in tragedy. Until that argument is convincingly made, people should be allowed to get high.
Any argument for criminalization would have to factor in the fact that desire for drugs is a biological primative, and that people will always try to get drunk and high. Drugs aren't going away, and criminalizing them will inevitably lead to a crime-run black market, which carries its own social costs. The question isn't just, "is the personal freedom outweighed by the social cost," it's "is the personal freedom plus a social cost outweighed by a different social cost."
For many, many people, pot is a fun time and as harmless as a couple glasses of wine. For a few, it's a problem. Pot should be treated as a public health issue to the extent that it is, but it shouldn't be seen as a criminal issue.