What power does the United States Supreme Court have regarding state laws?

The United States Supreme Court possesses the authority to declare state laws unconstitutional. This power is rooted in the principle of judicial review, which allows the Court to determine whether legislative acts align with the Constitution. If a state law is found to conflict with the Constitution, either as interpreted by the Supreme Court or as a matter of federal law, the Court can invalidate that law. This process is essential in maintaining the supremacy of the Constitution over state legislation, ensuring that individual rights and federal standards are upheld across the nation.

The rationale behind the Court's ability to declare laws unconstitutional stems from the Constitution's role as the supreme law of the land, as established in Article VI. This power is a crucial check on state legislatures, allowing the Court to intervene when state laws infringe upon constitutional protections. The Court's decisions in such matters set important precedents that guide future cases and legislative actions.

In contrast, endorsing all state laws or modifying them at will would undermine the principle of federalism and the states' authority to govern themselves. Reviewing state laws for accuracy presents practical difficulties and does not fall within the Court's purview, as it focuses on issues of constitutionality rather than merely evaluating legislative correctness.