Alleging an injury after the fact is all fine and good for the legal system's Civil law methodology, and while such procedural rules may be sufficient to mitigate disputes between two parties, it is certainly insufficient when dealing with damages and injuries which may affect thousand or millions of parties. When the public is to be put at risk of serious injury, it becomes imperative that officials take all appropriate steps PRIOR TO THE FACT of a potential injury to alleviate or mitigate any potential damage as a result of it.
One State cannot build nuclear devices and allow their street gangs to play with them. Such recklessness puts States downwind from the fallout zone at risk for death or injury. No! While "prior restraint" may be prohibited in our legal system, it is a required part of any activity which shows serious potential at being a danger to the public at large.
Consider Typhoid Mary. They ended up having to lock her up because she continued to spread typhoid wherever she went. Her threat to the public at large was deemed to be too grave to allow the issue to be resolved by ex post facto injuries. Prior Restraint was permitted in her case because the threat to the public was just too great.
Now I am not suggesting the legalization of Marijuana is in this category of drastic and obvious potential danger to others, but the legalization of hard drugs definitely is in my opinion. The problem for marijuana is that the arguments being advanced in favor of it work just as well for the harder drugs, and so they are connected by the same philosophical thread.
Whatever argument justifies Marijuana on the basis of "rights" also justifies Cocaine and Heroin on the same basis, and those are simply a dire threat to any society which will tolerate them. It is very like the issue of "Gay Marriage", if such should be enacted into law, will also justify Polygamy.
If you honestly belive any state would do this, then you need to find somewhere else to live. If you don't really believe they'd do it, then you need to stop building strawmen. You insult the intelligence of everyone else when you try to put crap like that out there as a rational argument.