Actually, having pot illegal is actually better for the government that having it legal. I smoke pot, I admit it, but truthfully, I started smoking it to "be cool" and fit in with the rest of my friends back in high school (I'm 21 now). Now, you make pot legal, and all the kids who want to be bad won't start smoking pot...they will find the next illegal substance that is readily available, such as cocaine, ecstasy, etc. Instead of a kid smoking a harmless joint to fit in, he snorts a harmless line of coke to fit in, and what you will end up with won't be pretty. If you go to Amsterdam, Holland, where pot is legal, the #1 drug there is not even pot, it's cocaine. People are more attracted to things when they are illegal, it gives them a sense of excitement, breaking the law and all. Tobbaco and Alcohol are both highly ADDICTIVE substances which is why both are widely used today, even though they are legal.
Hope that all makes sense...