Milton Friedman
wrote some on that:
The question of advertising is a very difficult question. I must confess that my libertarian instincts lead me not to want to prohibit advertising, and yet I am repelled at the notion of seeing a pretty young lady on the television screen saying, smoke my brand of cocaine instead of his, or my brand of smack or crack. So I am very much torn on the question of advertising, but again we don't have to decide all those issues. We now prohibit much advertising of hard liquor, and that is why I tried to say let's treat drugs the way we treat alcohol now, which is a mixture of regarding it primarily as a medical problem, but on the margins, on the fringes, as a criminal problem.
but nobody's allowed to mass-market it the way, say, Marlboro would. My main concerns about legalization are mass-marketing, drug use as a criteria for receiving disability payments(you can't work due to drug use, therefor you are disabled), and the US being drawn into guaranteeing the purity of the product.
What are your thoughts?