White House on State Pot Laws
It is important to recognize that these state marijuana laws do not change the fact that using marijuana continues to be an offense under Federal law. Nor do these state laws change the criteria or process for approval of safe and effective medications, including marijuana.
Many of these state laws began in order to create a legal defense to state criminal possession laws or to remove state criminal penalties for purported medical use of marijuana. Since then, many have evolved into state authorization for state-based production and distribution of marijuana for purported medical purposes. These state laws vary greatly in their criteria and implementation, and many states are experiencing vigorous internal debates about the safety, efficacy, and legality of their marijuana laws. Many local governments are even creating zoning and enforcement ordinances that prevent marijuana dispensaries from operating in their communities.
There are critical differences in marijuana laws from one state, county or city to another. For more information, see the chart, excerpted from information from the National Conference of State Legislatures (NCSL).