You can't ban alcohol because it's been proven that it doesnt work or have you forgotten about the prohibition era?

You can't ban the sale of tobacco either because its been proven that any attempt to soft-ban it like they have done is Australia by raising the prices enormously has simply created a black market that the government has no control over.

Finally, the war on drugs which has cost hundred of billions of dollars worldwide has completely and utterly failed. You can get drugs delivered to your door step in any major capital of the western world today. The quality is better than before and the delivery is fast and discreet.