what is the process for decriminalization of MJ nationally?
Very simple. The Attorney General announces suspension of enforcement of laws for personal use and possession by adults but maintains enforcement and penalties for distribution to minors or for public use.
That was the situation in New York City during the 60s and 70s. There were head shops all over the place. Sears sold bongs, pipes, screens and rolling papers in their tobacco shop. Pot plants were growing in back yards and my across-the-street neighbor had some plants growing on his brownstone roof in Park Slope, Brooklyn. The laws remained on the books but the cops were told to avoid bringing in any bullshit marijuana arrests. Pot was no big deal.
Back than the price of an ounce of decent "ditch weed" was around $20 for an ounce and the finest hydroponically grown Indica sinsemilla could be had for around $75 (now $350 - $500). During that blessed period crime was way down because fewer cops were wasting time on marijuana arrests, the City saved a lot of money -- and there were no problems because of it.
Then came Ronald and Nancy Reagan, who did to America what syphillis does to a living organism.