That RSA pretty much mirrors the Federal "prohibited person"
What is usually refered to is the ""Supremacy Clause" . Where the lower government bodies, in this case the states can not make laws or allow activies that the Federal law restricts or prohibits.
That isn't true though, functionally speaking. The state can allow anything it wants. That does not mean, however, that a citizen would be immune from being federally prosecuted under federal law, but it does alter things like how enforcement is conducted.
For example this occurs all the time with immigration laws. Lots of states (like MA) don't have a de-facto policy of punting illegal immigrants to the feds, nor are they required to by law, despite the fact that it is often pretty evident that the person is here illegally. Obviously some states like AZ are trying to change this.
We also see this with decriminalization of weed and the like, as well. (look at medicinal MJ in CA, as an example of the state not referring cases for prosecution. )
-Mike