Every day there are more and more stories in mainstream media outlets about Prop 19 and the growing national movement to end marijuana prohibition. That alone is a promising development. But what’s even more telling has been the way the tone of the coverage is starting to shift from asking, “Should marijuana be legal?” to, “Is marijuana going to be legal? And if so, when, where, and how?” Check out just three examples from today: Wall Street Journal: “Democrats Look to Cultivate Pot Vote in 2012” Democratic…