Smoking marijuana was once viewed as an act of political dissidence against the Vietnam War. Today cannabis is recognized as an invaluable medicine that's generated billions of dollars in revenue in states where it is now fully legalized.
The federal U.S. Drug Enforcement Agency (DEA) still lumps cannabis in with heroine, LSD and ecstasy as a Schedule 1 (illegal) drug. Yet, a total of 29 U.S. states and the District of Columbia now have some form of legalized marijuana. And eight more states—four of which adopted the measure in November 2016, and include California, Nevada, Maine and Massachusetts—have legalized recreational use of the plant.
A 2013 survey found a majority of physicians— 76 percent—approve of the use of medical marijuana. So why was it illegal for so long? Why won't the federal government legalize it now—and what would happen if they did?