MINNEAPOLIS (WCCO) – The voters in Colorado and Washington State were clear in approving ballot initiatives to make using small amounts of marijuana legal. But the federal law is equally clear, classifying marijuana as an illegal drug under the Controlled Substances Act. So how can a state pass a law that contradicts federal law?

“It’s hard to imagine the chaos that would result if state by state you had one state legalizing, one state not legalizing,” said Colorado Gov. John Hickenlooper.

Typically, states have the authority to set laws regulating criminal activity, said Dale Carpenter, a professor of constitutional law at University of Minnesota Law School.

“The Constitution makes it clear, in the event of a conflict, federal law prevails,” he said.

But right now, no one knows precisely what that means.

“The department’s enforcement of the Controlled Substances Act remains unchanged,” Justice Department spokesperson Nanda Chitre said. “In enacting the Controlled Substances Act, Congress determined that marijuana is a Schedule I controlled substance. We are reviewing the ballot initiatives and have no additional comment at this time.”

This means Colorado and Washington will no longer be enforcing certain laws, according to Carpenter. Washington and Colorado will not enforce their laws banning recreational use of marijuana.

But the federal government could still enforce its laws.

“Those people are still subject to potential federal liability,” Carpenter said.

For instance, the federal government did take Arizona to court in 2010 over its immigration law. That is an option here, of course, but the attorney general hasn’t said what will happen.

According to Carpenter, states have always been the laboratory of new laws. Minimum wage started in the states, as did the movement to end prohibition.

“This could be the beginning of a trend that could change federal laws. Or it could stop. Sometimes the states experiment with things that turn out to be really stupid,” said Carpenter, pointing to the legalized prostitution in Nevada as an example of an experiment that stayed in that one state.