The issue focused on political opposition to federal legislation known as the Senate legislation to legalize medical marijuana. Some medical marijuana advocates were concerned that the legislation would raise federal enforcement costs and federal enforcement laws would reach medical marijuana patients.

In his decision, Justice Justice Anthony Kennedy wrote that the federal law criminalizing medical marijuana was constitutional.

"It is therefore constitutional for Congress to criminalize the possession of marijuana for medical purposes," Kennedy wrote.

He added that the federal law could not criminalize medical marijuana because