How about cut the smack with a drug that will make people very sick but does not do any real damage and then release it on to the street. What do you think will happen?
Google paraquat.
What if your next hit might be your last? I thought of this back in the eighties when a lethal batch of heroin effectively eliminated demand in NYC for a couple of weeks. The dealers were actually complaining publically that they were getting squeezed. It was bizarre.
Of course, it's an unworkable idea. It would be a litigation nightmare at the very least, and a full blown civic disaster at the worst.
But then again, who says the government has to be involved?