Yeah, kind of like that.
Medical states are interesting though in the sense that they allow cannabis for medical usage, where as it is entirely illegal on the federal level.
So, in these cases they have relaxed federal law. It is a contentious issue, gets into the whole states rights v. federal authority...
Could also be the case on the state/county level, where a county could be more lenient on laws than the state, but individual counties do not have the legal power states have in relationship to the feds...its very convoluted.