Newsflash: The War On Drugs has NEVER worked. Not at ALL. Not in the SLIGHTEST. And it NEVER, ever, ever will. And the reason is very, very, very simple.
Good laws are always based on the practical idea that people must be restrained from injuring or taking advantage of each other. Such laws are always written by reasonable people, and they ALWAYS make the world a better place.
Bad laws are always based on the nutty idea that certain behaviors are "moral" and other behaviors are "sinful." Such laws are always written by religious idiots, and they ALWAYS cause wars, suffering, hatred, corruption, bloodshed, terror, waste, and chaos.
So, you see, you might just as well ask why it would not work to have a War On Stamp Collectors, or a War On Chocolate Lovers, or a War On People Who Sing In The Shower, or a War On People Who Like To Have Sex While Wearing Naughty Lingerie.
But actually, the War On Drugs DOES work very well for a certain privileged class, consisting of Cops, Lawyers, Judges, Prison Guards, and Drug Dealers. All of those people do VERY WELL because of the War On Drugs. And none of THEM would change it for the world.
EDIT: Can't resist calling attention to Marilyn's report that in Hungary the authorities put bars on the windows of the lowest floors of the jails. (Wait for it.) To stop jumpers. (Ba-da-BOOM.) In Hungary This is what Hungarians do. (Ba-da-BOOM.). Notice this is not a Polish joke It's about Hungarians. (Ba-da-BOOM.)