The real problem with drugs is not Mexicans supplying drugs, no matter how vicious and murderous the drug cartels are. When there is a demand, there is always going to be a supply. It's an economic law, and no one can stop it. Nether is the problem the demand for drugs by Americans, no matter how many of them are the kinds of people who want to do nothing but take drugs. As a wise man once said two thousand years ago, the poor are always with us. Not financially poor, but poor in spirit and character.
The problem is that which gets in between the supply and demand: the State. Specifically, grossly overpaid, underworked, not-very-bright, self-deluded bureaucrats who think the force and fraud of the State can stop both the supply and the demand, though killing and prison.
Let's do a thought experiment and imagine all the Drug Warrior bureaucrats are shipped off to Hell, which is where all of them are going away, and quite deservedly so. Then let's make drugs legal.
What would happen?
Within one day the drug cartels would collapse, since their billions of dollars of profit would immediately disappear—poof, just like that. All the violent crime, including murder, associated with illegal drugs would evaporate on the spot.
The demand for drugs would still be there, but the crime associated with getting the money to pay for the drugs would disappear. Our prison population would cease exploding, since many of those incarcerated are there for drug offenses.
Would people stop using drugs? No. But the problems associated with getting the drugs would disappear. Would real crimes disappear? No. But crimes created by State interference would.
What has to be discovered is how many real crimes would remain when the "crimes" created by State interference cease to exist. Thought experiments can only go so far with that.
As Thomas Sowell and many others have noticed, there are very few solutions in life, only trade-offs. The problem with the lackeys who work for the State is that they think there are solutions, always involving laws, guns and prisons.
If drugs were legal, there might be an increase in drug use. No one knows. If there is an increase, that is the trade-off of making drugs legal. But at the same time, all of the horrendous problems caused by drugs being illegal would disappear.
There is one big problem that would be solved with making drugs legal: no more Drug Warrior bureaucrats. It's not even a trade off. It's one of the few cases in life where there is a solution with nothing bad created someplace else.
That is a solution I think everyone can live with. Except, of course, for the bureaucrat who would be off of the taxpayer dime and have to get real jobs. That is, if any of them are qualified for anything in the private sector, and I really doubt that.