Who provides the final rulings on the constitutionality of the state and local laws?

The final rulings on the constitutionality of state and local laws are provided by the judiciary, primarily through state supreme courts and the U.S. Supreme Court. State supreme courts interpret their respective state constitutions, while the U.S. Supreme Court has the ultimate authority to interpret the U.S. Constitution and can overturn state laws that conflict with federal constitutional principles. Thus, both levels of courts play crucial roles in determining the constitutionality of laws.