If I remember correctly, Lew Rockwell predicted this would happen here on the blog more than a year ago. As more and more bankrupt state governments seek revenues, taxing marijuana looks more and more attractive. The same thing happened during the Depression with alcohol, ending prohibition despite the howls of all who possessed that "Puritan yearning to browbeat and injure, to torture and terrorize, to punish and humiliate all who show any sign of being happy." At least that's what Mencken thought.
Both California and New York are floating the idea, specifically for revenue reasons. Once the grim reality of tax revenues sinks in, the states will get a lot more desperate than they already are. The property tax revenues still reflect pre-crash valuations. New post-crash property values will start to slash property tax revenues in a couple of years, and then we'll see a lot more enthusiasm for the Pot Tax.