If we ban drugs, I think it should also apply to jackasse or daredevils. People (including children) should not climb tall trees or scale the Brooklyn Bridge with no reason. Why should anyone get subsidized medical care (and it is subsidized even if they pay for it) for falling off a tree that they had no business climbing? In the same train of thought, maybe we ought to close down all amusement parks and only allow people to drive to work or to go buy groceries. People driving or riding the bus puts them at risk of accidents and society suffers from these accidents.

Not to mention healthy diets should be strictly enforced, along with mandatory exercise regimes to reduce the public burden of obesity and poor health.

Just because we have not found an airtight reason to draw a line at a particular spot, does not mean that there should be no line.

Sure, I can grant that. Now we just need to define the line itself—its expressed purposes and guiding principles. Once we agree on the principles of the line, we can start working on the contours of where the line is drawn. Unfortunately, we keep jumping into drawing [and erasing] lines without enough discourse regarding the principles of those lines. The drug war is only one such example.