Prohibition does only damage to society and we have to be very naive to believe in the extreme incompetence of all governments that fail to see where the source of the "drug problem" is. It would be foolish of us to think that all those well educated people that create and execute our laws are incapable of figuring out that the regulations and treaties on prohibition are beneficial only for criminals and terrorists. Prohibition opens up a huge very lucrative market that is exclusively reserved to criminals. It's hard to wrap your mind around the idea that those who are fighting the war on terror don't realize that their war on drugs is funding the terrorists. Drug prohibition is the golden goose for terrorism.
The war on drugs is a war waged against the most vulnerable parts of society. This is not a new tactic, dictatorships and in particular fascist regimes always blame the weakest people for the existing socio-economic problems and start fighting against them. Putting poor people in prison or bombing poor people in other countries doesn't solve any of our problems, but it gives a perfect distraction for the masses that are reassured that efforts are invested in fighting non-existing enemies. The two groups that benefit most directly from prohibition are the drugs lords and the terrorists who make billions of tax free dollars every year.