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

The final rulings on the constitutionality of state and local laws are provided by the Supreme Court of the United States. The Court interprets the Constitution and has the authority to overturn state and local laws that it finds to be unconstitutional. Additionally, state supreme courts can also rule on the constitutionality of state laws, but their decisions can be appealed to the U.S. Supreme Court if federal constitutional issues are involved.