Washington DC is one of the 23 US statesWashington DC is one of the 23 US states that have legalized marijuana for medical treatment. The nation's capital approved the "Legalization of Marijuana for Medical Treatment Amendment Act of 2010" on May 4, 2010, after receiving a 13-0 support from the Council of the District of Columbia. It was then signed on May 21, 2010, by the Mayor. People, patients, and caregivers, who would like to become a part of the medical marijuana program in DC have ...