Prohibition came around because people came to believe that alcohol was the root of too many social problems and that by prohibiting alcohol production and sale etc.., that these social problems would be cured. They weren't. Instead, illegal activities flourished... smuggling, bootlegging, organized crime really took off, public officials were easily corrupted, and convictions were often hard to get because the jury was made up of people who wanted to drink. And when people went to a speakeasy to drink, they didn't just go to have a few... they went to get drunk. As a result, the 18th amendment was eventually repealed.
We are seeing the same thing happening with marijuana to a point. I don't know if public officials have been as easily corrupted with marijuana specifically, but I'd be really surprised if no one on the enforcement side of the equation was taking a payoff related to drugs at any given point in time. Some things are becoming more apparent, though.... there very well may be social evils associated with marijuana, but very strong efforts over a long period of time have failed to stop marijuana use, and the social costs of marijuana specifically aren't nearly as clear as they are, say, with heroin, cocaine, meth, or even alcohol. So public support in favor of decriminalizing and even legalizing marijuana has been growing and if things don't go to hell in those states where it is legalized, that trend will probably continue.
With respect to other, harder drugs like those I mentioned... heroin, coke, meth, molly, et. al.... those are a long, long way from getting legalized or decriminalized anywhere. I don't think there are nearly as many users of those harder drugs, for starters, while the social costs seem to be much more easily defined. There is no growing support for decriminalization of the harder drugs.
Should there be? Since we don't have those laws, they should not be. Per se. In that regard, what are laws, but a set of rules by which a society agrees - voluntarily or involuntarily - to abide. If a group of citizens don't like it and they are numerous enough... they can go start their own country. That's how the U.S. got started. That very well may be how ISIS gets a country of its own. A group of people who want to live together by the same set of rules. And if that means they don't want others using heroin around them - and everyone feels that way - that then becomes law, and the heroin user will abide, either voluntarily or involuntarily... or he can start his own country.
That's how we live.
So the first step in getting any change in laws is public support. That is what MADD did to beef up the drunken driving laws. used to be a nuisance bust for the cops, not worthy of their time. MADD changed public opinion and that wound up changing the laws.
Marijuana started changing public opinion with NORML. There are other groups that are politically active with respect to decriminalization or legalization of marijuana, too... none that I know of for harder drugs.
Though I understand that NAMBLA would like to change public perceptions of... well... you know.
Anyhow... I guess I'm just as glad the harder drugs aren't legal or decriminalized. If cocaine were easily available and not criminal, I'd probably be dead by now. And I doubt I'd be alone in that. As for the Portugal model... it has its merits. As I interpret what they have done, they are now aggressively pushing addicts into treatment programs. Over the long-term, there may be a lot to say for that approach. I'd need to know more about how it's working over there. Even at that, I would see it as a states rights kind of thing... again, a society can determine the standards by which they live. In the U.S., those societies can be broken down into smaller and smaller groups, states being one of those groups that may impose its standards across its members.