http://www.pbs.org/kenburns/prohibition/
Before I watched it I thought "how could people be so stupid as to think they would ever ban alcohol". After I watched it I was like "oh wow, people drank on average 1.5 bottles of hard alcohol a week? Drunks were everywhere? Opening a bar was super cheap because the alcohol companies subsidised them. Ok, maybe I get why people would vote for prohibition".
I'm not saying it was a good idea. It was clearly stupid idea which the rest of the doco made clear and is directly analogous to the war on drugs.
Another POV that gave me a new perspective was the idea that legal drugs (alcohol) kill way more people than the war on drugs kills. 3+ million a year die from alcohol. (http://www.who.int/substance_abuse/facts/alcohol/en/). Legalizing a bunch more drugs may have the unintended consequences of killing an order of magnitude more people than the war on drugs.
I'm not saying I'm for the war on drugs. All the unintended consequences of that are horrible as well. The USA's police state, seizure laws, militarization, etc. But, the idea that we'll end up possibly causing 10x more death from legalization makes me wonder if there's some middle position