Libertarians should show us where, exactly, the US Constitution says that drug fiends, due to their addictions, have rights to commit so many different crimes against other Americans. They steal, murder, consume far more than their share of tax revenues, entice kids to join them, violate families in several ways...all because of their drug-addled nature. The list of their crimes against the rights of law-abiding Americans is long.
As for “legislating morality,” the Constitution itself legislates morality. So it is with the laws of the states: the laws that are most often used to put drug zombies in prisons. Our legislatures should pass laws to execute them.
You have just described Congress.