Marijuana is illegal for any reason under federal law, but states have boldly experimented with allowing its use anyway, starting with California 20 years ago.
Some states have made the drug legal for medical purposes; others have removed jail sentences for carrying small amounts; and some let adults 21 and older use it for any reason.
Here's a look at where the states are on pot as well as legalization developments in other countries:
Eight states allow people with certain medical conditions to use marijuana, according to the Marijuana Policy Project, a pro-legalization group that tracks state pot laws.
Arizona, Illinois, Michigan, Montana, New Jersey, New Mexico, Pennsylvania and Vermont each have their own lists of ailments for which sufferers can use the drug with a doctor's recommendation.
The drug cannot legally be prescribed in any state, because it has no accepted medical use under federal druglaw. But some doctors are willing to recommend it under certain conditions.
