It sucks but the war on drugs never worked. Ever. No matter what policies they put in place, it still doesn't work. Because they're doing it wrong. Never arrack the supplier, always attack the addict.
Only issue there is there will always be addicts and idiots that want to try it (then get hooked on it), even the really nuts shit like krokodil and bath salts.
The legal system also deal with posession with a slap on the hand, rather than a harsh sentence. Hence attacking the addict currently does not work (and it's unlikely it will).
I get that. But as I said, alcohol is 1,000 times worse than pot. I know there are issues with marijuana as much of my family including myself are allergic to it. But we are very rare. How many people have actually died from pot? If you support drinking of any level and don't support marijuana on any level then you've either been fed lies that you've been suckered into believing or you're hypocritical. That's just how it is.
Marijuana causes schizophrenia, hence how many people have died from schizoprenics or those in a form of psychosis as a result of marijuana.
Then again I suppose it's a slippery slope arguement because how many people have died at the hands of drunk drivers.
But that said, legalisation is never the answer to solving any crime. By legalising marijuana not only do you them drastically increase the amount of people drug driving (not just drunk driving), or both... but you also increase the potential victims of crime as a result of people smoking marijuana.
Given the ever tightening smoking laws, it'll soon be the case (I honestly believe), where smoking anything (bongs/joints/vapes/cigarettes) will only be allowed in a persons home. Imagine walking in public and people are wandering around smoking bongs.
Then there's the issue around people in regular occupations turning up stoned.
Finally the other big issue is "what abouts". Once you legalise marijuana, people will want ecstacy, then cocaine, then heroin, etc etc legalised, and based off the arguement "well marijuana is also a drug".
As to what the solution is... if legalisation isn't a solution, and the courts are treating possession as softly softly, then going after the dealers/manufacturers really is the only way to stop it (and hitting them harder than ever).