Heroin is just another opioid in the same drug class as morphine and dilaudid.   It happens to be a wonderful drug for cancer pain and is used for that in other counties similar to how morphine and dilaudid is used here and sold in pharmacies. 

Unfortunately heroin shares the same problems as morphine, dialudid, Percocet, etc.  Unlike cannabis, they are physcially addictive and can kill you.

But in answer to your question, “how do you make an illegal drug legal?” You demonstrate that is is useful for treating certain diseases and conditions without having worse side effects than the disease it’s treating.  Once you demonstrate that, we have a moral and ethical obligation to make that treatment available. 

Currently medical cannabis patients must be seen and evaluated by a licensed physician before being prescribed cannabis.

Out of curiousity, what are your thoughts on morphine, penicillin, and aspirin?