Well there are bound to be some conspiracies which are true. For instance, the 9/11 attacks were carried out by a conspiracy of Muslim suicide-bombers.
I generally don’t hold with conspiracy theories, but I can’t think of a reasonable explanation for why drugs are illegal. Firstly, consider the demand. Surely there are enough people who want drugs? Secondly, the laws are completely ineffective. There is so much money to be made selling drugs that the authorities cannot enforce the laws. Thirdly, the money thus generated is used to empower the violent and the cruel and to subjugate the weak. Fourthly, the government looses all control over quality of the product and is unable collect tax revenue from profits generated.
I’ll take a weak stab at it and say that those who stand to loose the most would be the drug lords, and that thus they must somehow be manipulating things. However, even stoned as I am, I find that a little hard to believe. I will leave it up to my fellow skeptics (perhaps more sober?) to provide a more convincing answer.
Thank you. ;D