“There just isn’t enough evidence to support that law. And there’s a very compelling reason to believe that people who are not impaired may be charged with driving while impaired,” says Tvert.

Colorado also just passed legislation that requires any publications that have marijuana related advertising to be treated like pornography and kept behind the counter.

Three publications have already filed a suit to block that provision. 

In terms of medical marijuana, states must also deal with regulation of dispensaries, transportation of the drug and what constitutes a doctor/patient relationship.

The amount of cannabis a patient can possess is another gray area among many.

For instance, under Michigan law, a patient can legally possess up to 2.5 ounces of marijuana, unless it is medically necessary for the patient to have more. 

Will the Fed legalize marijuana?