Why not leave it to the states to regulate intrastate mj as each one sees fit?
I have friends who are life-long conservatives and business owners who smoke dope.
It was, after all, initially banned because the cotton growers did not want to compete with the superior hemp product and marijuana is a byproduct of hemp.
And then it is difficult to tax so the government does not want it to be legal. But tax it like cigarettes and alcohol and save a lot of money waging the war on drugs.
of course, it is a state’s right, as almost all rights are supposed to be.