On Election Day in 2012, voters in Colorado approved a ballot initiative legalizing the recreational use and sale of cannabis, making the state the first in the U.S. to do so.

Ten other states, Washington, D.C. and Guam would go on to legalize the drug in the next seven years as public support for legalization rose rapidly, despite the fact that marijuana was and remains illegal at the federal level.

Some strains of the cannabis plant – often called marijuana or weed – contain a psychoactive compound called THC that produces a “high” when ingested.

Today, support for marijuana legalization has become mainstream among Democratic politicians, and some Republicans also back the idea. State legislatures are grappling with if and how to legalize the drug, while a slew of marijuana-related bills – including those aiming to legalize it on the federal level – have been introduced in Congress. […]