I support broad legalisation plus taxation. Very similar to what's common for alcohol and nicotine around the globe.
Despite being legalised, alcohol still causes problems. But I doubt banning alcohol would decrease problems on net (especially compared to heavy taxation).
Banning something is not the main problem, per se. It's banning something the people want. You could ban durians in the US and maybe a couple would get smuggled into an Indonesian neighborhood, but it would never turn into a gang war. If you look at the countries that have banned alcohol, they are also mostly the countries where the culture has strong and effective prohibitions on alcohol, and people police themselves for the most part.
Do keep in mind that the US did have a strong abolitionist movement as part of their culture. And still has! The Puritan heritage that's against any fun is strong with them.
Another side note: restrictions on smoking in restaurants, workplaces and other areas largely preceded shifts in culture in many jurisdictions. So legislation can predate changes in culture. However, I don't know whether that's just a coincidence, or if there's a causal effect? Also, legislation that makes desirable things inconvenient, but doesn't outright ban them, probably has a much, much lower chance of turning into gang wars. (That's a big part of why not-too-high taxation works fairly well for drugs.)
Yet another tangent: we often see drug production and distribution as part of organised crime. But economically, it is perhaps better to view the drug business as a victim of organised crime: as you can see by the legalisation of alcohol and more recently cannabis, people in the industry would much rather just do their business and satisfy customers; but organised, violent crime can become a parasite on any activity that's shut off from recourse to the police and legal system to defend themselves.
> Do keep in mind that the US did have a strong abolitionist movement as part of their culture.
To be sure. The 18th Amendment was passed by a majority of Americans. However it outlawed, "intoxicating liquors". It was the Volsted Act, passed to be the nuts and bolts of enforcement for the 18th, that outlawed everything, much to the surprise and dismay of a fair faction of its supporters. The Presidents of the United States maintained a liquor cabinet in the White House throughout Prohibition. The actual implementation of Prohibition lost many of its supporters and the negative unintended consequences of prohibition lost many more.
> But economically, it is perhaps better to view the drug business as a victim of organized crime
Of course. Milton Friedman said, "If you look at the drug war from a purely economic point of view, the role of the government is to protect the drug cartel."
