Drug cartel leaders - much like the booze running from organized crime during the 1920s - are a product of prohibition. Prohibition creates insane demand, and look where that's gotten us.
As a first step, legalization and treatment instead of prohibition and punishment needs to be explored.
Yeah, but a lot of those drugs really
should be illegal. You can just drop dead from cocaine or methamphetamine ... these drugs have some serious cardiovascular side effects. And you wouldn't need to try very hard to drop dead from these either (even a very small dose of amphetamine can make your heart flutter ... and that's just ADHD medication, not meth). Not to mention the CNS effects (psychosis being the scariest). That's not anything like alcohol, tobacco, coffee or over-the-counter drugs.
I'm really not sure how you deal with the drug issue. Legalizing it would reduce the number of prisoners, while exposing the public to very dangerous substances either directly or indirectly. If you thought DUI was bad, some of these drugs induce psychosis ... which is scarier than DUI. I would not want to be around someone disconnected from reality (far more removed than a drunkard).
EDIT:
It came to mind that if you legalized at least some of these drugs, the crime rate may actually
increase (because someone detached from reality can do some really strange things). So it's not clear to me that there would be a decrease in prison populations.