The "take drugs and you'll get expelled" policy is a categorical "you are not allowed to take drugs" assertion with no satisfactory justifications. Whereas even the most defiant pupil can probably acknowledge the common-sense value of a rule which disallows climbing on the roof, drug-taking is perhaps the most controversial and newest offence in school rules, a particularly huge problem of this generation and beyond. The issue requires the utmost education and explanation. If a pupil were to ask 10 teachers why heshe was not allowed to take drugs, heshe would probably get eight different and possibly ill-informed answers.
Furthermore, so widespread is the use and accessibility of cannabis (and even speed and Ecstasy) that such "black and white" policies can no longer be reasonably expected to work.
No school would think of expelling pupils if they were caught smoking cigarettes - apart from any ethical considerations, no school can afford to lose as many pupils as are likely to be caught smoking. The present trends suggest that cannabis-taking will reach (if it hasn't already) such proportions as to render automatic expulsion an unworkable penalty.
I have encountered many 14 and 15-year-olds who have tried both cigarettes and cannabis in the space of a fortnight; such rapid "ascendancy" from cigarettes to drugs would have been unthinkable five years ago. What is emerging among some teenagers is a preference to smoking cannabis to cigarettes. The perturbing factor lies with their ability to justify this preference with rational arguments: for example, cannabis is less health-threatening than cigarettes, it's not addictive and so on. If pupils are rationalising the relative risks of drugs (whether correctly or not), surely it is time for schools to incorporate drug education as a high priority in the timetable, instead of just laying down rules. And a pre-requisite of such a move is that teachers themselves become well-informed.
Teachers must unite to collate all the arguments and facts about drugs, to find a way to present the information to pupils which will best equip them to judge for themselves. The question of whether cannabis is legal or not is neither here nor there: it is the function of law to assert what is allowed and disallowed.
Teachers, however, must (with the help of parents) adopt the unenviable moral responsibility of guiding their pupils in the right direction.
Corpus Christi College, Oxford