Sometimes when the state and federal governments have concurrent authority,the federal government can decide to regulate that area exclusively.In such a situation,the state law is unconstitutional according to the doctrine of federal subrogation.

Doctrine of Federal Subrogation

A legal principle allowing the government to take over the legal rights of a person to whom it has paid money, typically in insurance.

Concurrent Authority

Legal jurisdictions or powers that are shared by different governmental or regulatory bodies.

Unconstitutional

In violation of the principles or provisions of a constitution, especially referring to laws or actions that contradict a country's fundamental laws.