My personal opinion, don't flame me for it.
How is a law going to stop people who are going to do something stupid? Its not! If drugs were illegal, than there would be something like an under 21 law banning people under 21 from purchasing drugs. How do kids get drugs? By illegal drug dealers who usually make their own drugs, or in the case of Marajuana, grow their own. If drugs were legal, then these drug dealers wouldn't make a profit off the streets for small money, but instead get large corperations, lets say Walgreens, to pay them hundreds of thousands of dollars. Meaning drugs on the street would be signifigantly redused.
If people want to screw up their lives with crack or cocain, then allowing them to legally do it would mean more money to the government. Which brings me to something else. Taxing. If the US government puts a tax on drugs, it would do wonders for the economy.
And then there's DUI's. Well simply, if your going to smoke Marajuana, are you really going to leave the house anyway? And if you do, well, we have drunk drivers too, so give them the same punishment.
Drugs would bring cartells down. Think about it. The dealership being the Cartell. The private seller being the Walgreens. (odd isn't it?) And the BMW X5 being the drugs. The dealer sells the X5 for 30,000. But the private seller sells it for 18,000. Same features and everything, except this one comes with warranty!. And the private seller is selling it with 0 miles, straight from the dealer. Why would you pay the cartells if you could go to the Walgreens across the street and buy your drugs for a cheaper price, knowing you will get an unaltered product. This means effectivly making cartells go out of buisness.
Back in the early 1900's, they put a ban on alcohol similar to the ones on drugs today? Did it work? No!
Again these are just my opinions, flame me, ban me, do whatever you want to me. Well except for, I'd rather not say!