The point is that either you have reasonable basic liberties, or you don't. If you think an adult ought to be able to decide what they will or will not ingest, then how do you get from there to the authorities stepping into that decision using coercion? If you don't think an adult ought to be able to make those decisions for themselves, then I can't have a meaningful conversation with you.
I think you mean an adult can ingest anything he wants so long as it does not harm
others (suppose I ingest substance A and B which together form a powerful explosive,
right beside YOU. Do I have the right to ingest A and B. I think not).
Now, we should have a *meaningful* discussion of whether **some** drugs are such
that there consumption harms others to a sufficient degree to warrant prohibiting their
I think it is completely obvious that marijuana poses no such risk; not so sure
about crack cocaine (and, from another angle, potential cognitive enhancers,
steroids for athletes etc.)