No - people on drugs commit crimes, destroy their lives and the lives of those around them. The drug trade destroys families, neighborhoods, and communities not merely because of its illegality but because of its effects on the human mind and spirit. There is absolutely no redeeming value whatsoever, no reason, no excuse, and no purpose for drugs like crack. That's none - as in "zero" - and that is a rare thing.
In my mind, there are very few objects or substances in our world that rise (sink) to this level, so as to justify making them illegal. Now, many people would describe that last statement as a "libertarian" position, and I think it is. What it isn't is "absolutist" in the sense that one might believe if the Government can ban "A", it can ban "B" and then "C" and then "D"...etc. No, it cannot; not in this case, and not in any other. A single, vital condition (our Constitution) would be sufficient alone to break the "chain of inevitability", more about which below.
You want to justify legislating on perceived threat. That is exactly how dictatorships arise.
That might just be an overstatement. If drugs are banned... what? The Nazis are coming? You've got to make a more convincing argument than that, Radioman. As a rule, "slippery slope" arguments almost never work. The reason they don't is because they always depend on a theory of inevitability in which mechanisms of connection are presumed to exist regardless of relative condition, value and potential, as well as the incentives and disincentives for human action upon them. In other words: the entire framework of free will and written law is presumed powerless against the cascade of historical inevitability. Marx made an argument like that once, too. Didn't work out too well for him, as I recall.