1) cannabis is not a toxin. you can not die from consuming too much of it. That is a medical and scientific fact, not an opinion. If you disagree, you're just wrong.
2) Ending prohibition across the country will severely weaken the power of drug cartels. Prop 19 is the first step towards that goal. And yes, if we stop waging war on drugs, it will stop the drug war by definition.
3) There have been many studies done that say cannabis is easier for highschool kids to buy than beer. This is because cannabis is generally sold on the black market which does not ask for ID's. It will be harder for kids to buy bud if it's sold in stores rather than on street corners.