Uncooperative federal government has led to innovation on marijuana policy in more liberal, less religious states.

In the past two decades, 29 states and Washington DC have liberalized their laws on the use of medical marijuana - in defiance of federal regulations. A. Lee Hannah and Daniel J. Mallinson look at why some states have become 'defiant innovators' in this area. They find that if a state is more liberal and less religious, if the state ...