08/29/2013: Department of Justice announced it will not challenge state legalization efforts.

08/12/2013: Department of Justice changed policy regarding mandatory minimum sentences for drug offenders.

06/06/2013: Vermont decriminalized marijuana possession.

05/28/2013: Colorado governor signed bill regulating recreational marijuana.

05/17/2013: Illinois Senate approved medical marijuana bill.

04/23/2013: Supreme Court ruled marijuana possession not grounds for automatic deportation.

04/08/2013: Maryland Senate approved medical marijuana bill.

02/08/2013: Michigan Supreme Court ruled private sale of medical marijuana is illegal.

01/22/2013: Federal appeals court declined to change marijuana drug classification.

12/03/2012: Arizona judge cleared way for marijuana dispensaries.

11/06/2012: Washington and Colorado legalized marijuana in state ballot initiatives.

09/11/2012: Montana Supreme Court found no constitutional right to medical marijuana use.

06/24/2011: US lawmakers introducted bipartisan marijuana legalization bill.

10/19/2009: Department of Justice directed prosecutors to end raids on medical marijuana facilities.

07/31/2008: California court ruled that state medical marijuana program does not violate federal law.

06/06/2005: Supreme Court ruled that Congress has the power to criminalize the growth and use of marijuana for personal medical reasons.