Another thing we have learned from the war on drugs is that the higher prices caused by drug prohibition have led to ever more potent drugs. There is an economic reason for this. It is called the "Alchian-Allen Effect," named after two UCLA economists, Armen Alchian and William Allen. It goes like this: If a harder drug like cocaine sells for, say, $10 for a certain quantity, and a softer drug like pot sells for $5 for a similar quantity, the ratio of prices is 2 to 1. The hard stuff is twice as expensive. With a reduction of supply (caused by the wall, for instance) that increases the price of both by say, $5, the prices are now $15 for cocaine and $10 for pot. The price ratio is now 1.5 to 1. Cocaine has become relatively cheaper, which will induce many people to switch to the harder drug to get more of a "buzz" for their money.