Justice Louis Brandeis once said that the states should function as "laboratories," testing new ideas for possible adoption by the whole nation. We have seen enough over the past 16 years from the states that have legalized medical marijuana to know that the benefits are real and the alleged dangers overblown. With this data in hand, the DEA should reclassify marijuana to acknowledge its possible medical uses.
In Colorado and Washington, a bolder experiment is now underway. The rest of the nation should watch closely. It is possible that legalization will lead to higher crime rates, increased use of harder drugs, and other menaces that marijuana critics warn about. But if legalization in these states has few negative effects, we will have the strongest argument yet for why marijuana should be legal nationwide.