The upcoming Supreme Court case, to be argued March 28, will mark the first time America's highest court has ever considered the issue of medical necessity with regard to marijuana. Once the voters of a state have adopted an initiative or a state legislature has enacted a statute protecting the medical use of cannabis, the people of that state have compellingly expressed their public policy, even if that public policy differs from that of the federal government.
Federalism mandates that state public policy is entitled to presumptive deference.
A fortiori, it naturally flows from that case that there is also a parallel right patients in chronic pain or the terminally ill have to alleviate their pain and suffering when they want to live. The Justice Department is appealing that decision.