Based on Godwin's Law which states that: "As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches one."
This adage shows that when an online discussion about the legalisation of certain drugs is created, it is inevitable that someone will instantly pipe in and state how it is really unfair that Alcohol, Tobacco and Caffeine are legal, while Cannabis, Cocaine and Heroin are still illegal in most places.
After a certain amount of time, the discussion becomes cyclical and utterly pointless, with both sides being completely unmoved by the arguement put forward by the opposing side.
Many will argue that prohibition has been proven to fail and point ot the rise of criminal gangs in early 20th Century United states of America, through illegal distillation and distribution of alcohol, coupled with speakeasies.
The other side will often point out that the prohibition of many recreational drugs is in the interest of the safety of the majority of the population.
Basically, and again in a similar vein to Godwin's law, this law states that the first person to argue for the legalisation of certain recreational drugs] by using alcohol, tobacco or caffeine as a reference point instantly loses the arguement.
User 1: All drugs should be legal.
User 2: Boo hoo. I can't get any good coke because my stupid government have made it illegal, but they let people drink beer.
User 3: Another example of Terry's Law.