WASHINGTON — The Obama administration on Thursday said it would not sue to undo laws legalizing marijuana in 20 states, although it will monitor operations in those states to make sure they do not run afoul of several enforcement priorities.
Washington and Colorado recently began allowing small amounts of marijuana to be used recreationally, while 18 other states and the District of Columbia permit the use of marijuana for medical purposes.
http://www.nytimes.com/2013/08/30/us/politics/us-says-it-wont-sue-to-undo-state-marijuana-laws.html?_r=1