The war on drugs was also a resounding failure and society slowly turned against it. Almost all the legalization movements are grass-roots and push their ideas through ballot initiatives. There is a strange disconnect here: voters generally vote for legalization, if they have a say, but elected politicians are afraid to do the same because they worry about their electability.

I think that need to communicate without external interference is at least as strong in people as the need to light up a joint. Even in China, where controls on communication are very strong, people manage to find a way to circumvent the limits. Much more so in other autocratic regimes, such as Iran.