It must be consistent in its application. Prohibition systems have failed in this regard, they are full of inconsistencies even on what constitutes an illegal drug. Is there really a big difference between marijuana and cigarettes? Or alcohol? They have all been proven to be addictive if used regularly and they all produce negative externalities. Prohibition results in only a moderate reduction in drug use. Simply put, the high costs and numerous negative externalities outweigh the small benefits that restrictive policies produce. With this in mind, the natural conclusion is that a restrictive and prohibitionist policy is not an effective means of achieving the goal of reducing drug use. After all, economics is the study of how best to allocate scarce resources among competing players..