I’m completely against recreational drug “legalization” but am a staunch federalist about the issue. It should be handled by and in the individual states, not federally.
But there is a real hazard to a patchwork of states allowing it to some degree. States have margins, in which people living there often live in two worlds. What if a person lives in a state straddling city, working in one and living in another? This is a frequent condition. The cross-border risks of criminality when pot is legal in one and criminalized in another is a very real dilemma.
As long as there is no encroachment or demands on a criminalizing state by a neighboring legalized state, I’d be okay with it.
Now this is a respectable position. However, when it comes to internationally based drug organizations that smuggled product in from foreign countries, it becomes an issue of national significance, and therefore a Federal issue.
Also, one can make a fair argument based on the history of China between 1840 and 1960 that drugs constitute an existential threat to our society and to our government.