To add to the whole drug debate, I'm not so much in favor of legalising marijuana as against the logic that it's somehow categorically worse than alcohol. That said, if having alcohol as a legal drug is a mistake, that doesn't mean we should make another mistake by legalizing marijuana. Either both or neither should be legal.

There's obviously also a slippery slope argument that can be made here that says if we start legalising things, then we'll end up legalising a lot of stuff that is patently dangerous and which I think most would agree shouldn't be legal.