It helped that she was right. There are no "no go" areas for drugs, as several independent schools have found to their high-profile embarrassment. Schools which simply close their eyes to potential abuse are deluding themselves as well as denying their pupils the knowledge and confidence they need to say no.
It was significant, too, that what the minister said was based on skilled professional advice; on genuine consensus and the integrated strategy set out last month in the Government's green paper on drugs. Mrs Shephard's announcement was not moralising or headline-grabbing. Somehow, one knows that when the next school drugs shocker breaks, she is not going to be caught making attention-seeking comments.
It is true that, in voicing the fears of many middle-class parents, she was likely to gain in popularity, unlike the schools she enjoined to come clean on drugs. But she has set a clear example to local authorities, teachers and governors who have it in their power to educate the wider public in order to pre-empt the stigma that might attach to incidents or to individual schools taking an up-front approach. It is vital that parents not only understand but lend practical support to efforts to combat drugs.
That said, schools alone cannot make children "drug-proof", the Protecting Children Through Education campaign slogan. Again, Mrs Shephard was right: drug abuse is an educational issue. But it is part of a much wider need to promote healthy and purposeful living. Pupils should understand the dangers of drugs but that alone will not protect them from the curiosity, peer pressure, boredom or the desperate hopelessness that drives some to ignore the hazards.
The draft circular issued by Mrs Shephard this week talks of equipping pupils with attitudes and skills to avoid drug misuse as if it is a one-off immunisation process. Schools need time and help to work out what those attitudes are and how they can be encouraged. They need public support, too, in the shape of credible role models, and they need government policies less equivocal about tobacco and alcohol advertising.
Above all else schools need to be better as schools. What they are about is the antithesis of the drug-takers' live now, pay later hedonism. Deferred gratification is what the sociologists call working hard now for later benefits. To face their future and the world beyond school with hope and optimism rather than seeking escape in drugs pupils need faith in themselves and in that world. Inasmuch as teachers have access to the levers of the mind, they must use it to boost children's confidence and self-esteem, to provide them with a vision of a better world and the qualifications to face it. But only those who control the levers of the national economy can ensure there is a productive place for children to look forward to in that world.