The Dutch make an interesting and useful distinction between "hard" and "soft" drugs. When a Amsterdam police officer says, "I think drugs should be illegal and dealers should go to prison," they're almost assuredly talking about "hard" drugs like crack and heroin. Marijuana and hashish are considered “soft” drugs and were decriminalized in 1976.
The result is that "coffee shops" selling weed and hash appeared, since people knew you wouldn't get arrested for possession.
When the hard/soft distinction was made, the idea was to accept marijuana for what it is and allow people to buy weed without having to deal with drug dealers and guns and gangsters.
The hard/soft distinction is somewhat arbitrary. But no more so than our distinctions between legal, prescription, and prohibited drugs.
There is also some debate about whether to classify ecstasy and hallucinogenic mushrooms as hard or soft.
Dutch police generally support the hard/soft distinction and would not want to close “coffee shops,” even if they could. In speech, they use “drug” to mean “hard drug.”
When I asked a police officer to clarify the distinction between "hard" and "soft" drugs, she said a hard drug is one that, "if you do it wrong, you can die." That's not a bad working definition. Particularly because it presents the problem of drug policy as geared to saving lives, and not imposing morals or punishing deviants.
Of course I think all drugs should be regulated, but I would settle for a system where no drug user is jailed, violence is low, and drug use is seen as a public-health rather than criminal-justice issue.