There is an existing legal theory in the US legal system that a State would always have the last say in enacting laws even inforced by the federal government. This legal concept is known as nullification. However, the condition to nullify a federal in a State would be first, for the State court to prove that the law is unconstitutional. Then a legal process has to be done so that the State law can prove to the federal courts that the law enacted and imposed by the federal government is unconstitutional.
