What prevails when there is a conflict between a state rule and an interstate compact rule?

When there is a conflict between a state rule and an interstate compact rule, the compact rules have the authority of federal law. Interstate compacts are agreements between two or more states that are approved by Congress and thus acquire the force of federal law. This means that the rules established in these compacts take precedence over conflicting state laws. The rationale behind this is rooted in the Constitution, which provides that treaties and agreements made by states with each other, and approved by Congress, are significant in guiding governance across state lines.

The supremacy of interstate compact rules ensures that agreements made to handle common issues, such as resource management, transportation, or criminal justice, maintain uniformity and consistency among states involved. This is particularly vital in matters that cross state boundaries, as states must adhere to the interstate agreements to uphold cooperative efforts and legal clarity.