Legal Weed: Why not, it could be the new tobacco, right?

People in the U.S. smoke to much of this stuff already. Which means that they will pay out the nose for it, even if they don't want to. Legalize only special licenced individuals to grow, harvest, and sell the drug. Making the product cheap, easy to get, and of less quality. Add in the tax on such a product and you have a new way to keep the state going in school, welfare, and tax break funds. Then we could ban tobacco, which IR loves so much, and see if cancer patients stop popping up.