Colorado's amendment 64 just passed, as did Initiative 502 in Washington. Marijuana prohibition is gradually becoming a thing of the past, and simply needs one final push. Alcohol prohibition turned out to be more harm than good in the early 1900's, and marijuana prohibition is recreating the same situation. The bottom line is that marijuana prohibition enforcement costs the government 13.7 billion dollars annually, and puts well over 500,000 people in jail every year (sources cited below).
http://www.cnbc.com/id/36600923/The_Cost_and_Benefit_Arguments_Around_En...
http://www.huffingtonpost.com/2012/09/26/marijuana-legalization-in_n_191...