You may be suprised at the number of famous people who have used cannabis. We now have the example of British juries increasingly ignoring judge's instructions and acquitting cannabis users. A large percentage of the population has discovered that cannabis is relatively harmless. It is impossible to go back to the old regime of frightening them with tales of degradation and misery should they take a single puff from a joint. Before the Internet, I never realised that there has never been a single death attributed to cannabis use in over five thousand years.
Cannabis is more carcinogenic than tobacco and is likely to cause more cancer.
The smoked part of the plant, the bud, contains less carcinogenic substances than tobacco. The unused parts do have more though. Even then the average cannabis users only smokes a couple of joints at the weekend not twenty a day. I have seen the report from Glasgow regarding four people, three of whom smoked tobacco, used as an example of these dangers. Yet, most other reports say there is no link between cannabis and cancer.