[bsder]

> but I don't think we can treat pot as totally harmless for people under 30 and teens in particular because it seems like it's very harmful for some.

But I can say the same for alcohol and cigarettes and ...

While there are a few diehards, most sane people will not defend "marijuana is harmless"--even for adults. It's a drug; it does something to your mind; that's why you use it.

However, the increasing amount of data suggests that what harm marijuana does is in the same class as things like alcohol and cigarettes--which are legal, but regulated.