Congress approved a provision that effectively ends the federal government’s prohibition on medical marijuana. Thirty-two states and the District of Columbia have legalized pot or its ingredients to treat ailments, a movement that began in the 1990s. Congress resisted requests to allow states to decide their own path on pot for many years.

The new marijuana measure, which forbids the federal government from using any of its resources to impede state medical marijuana laws, was previously rejected half a dozen times. Ending the ban on medical marijuana signals a major shift in drug policy. “The federal government should never get in between patients and their medicine,” said Rep. Barbara Lee (D-Oakland).