Fortunately we do have a largely successful, bloodless war on a drug to learn from. Tobacco abuse is less than half what it was back in the early 70s in the US, and similar declines are seen in many European countries. Advertising campaigns, usage restrictions in public places and high taxes have been very effective, and also meant that the medical costs of treating the effects of tobacco abuse have been more than covered by tax revenues from it's sale in many countries.
While campaigns against alcohol abuse have not been as successful, mainly because they have not been as focused on reducing all usage, tax revenues have been high. Normalisation of low levels of use in appropriate circumstances and ammounts have also limited the harmful effects on most abusers and those around them.