Marijuana Use And Reasonable Accommodation Requests

I have received two inquiries over the past couple of weeks for guidance on a confounding issue: medical marijuana.  As I write this post, more than 20 states (and the District of Columbia) have some kind of legal medical marijuana or decriminalized marijuana policy on their respective books.  However, marijuana use is still unlawful under federal law generally and drug use (including marijuana) is specifically prohibited at affordable properties throughout the nation.  What should professional apartment management do when a resident submits a reasonable accommodation request that he or she be permitted to smoke marijuana at home pursuant to a request that has been medically verified and looks to be in compliance with state law?