I agree any State should be able to institute any law on drugs they choose within their own lawmaking process that does not interfere with the Constitution or the legitimate rights of the other states.
If a state were to institute a law to make the use, possession or sale of marijuana punishable by death, I would support their authority to do so.
As I point out about libertarians, they support many of the same things as the regular left, and they support them, and oppose conservatism, at all levels of government.