What must state courts do regarding federal law?

State courts must enforce federal law due to the Supremacy Clause of the United States Constitution, which establishes that the Constitution, federal laws, and treaties made under its authority are the supreme law of the land. This principle means that when state laws conflict with federal laws, state courts are obligated to uphold federal laws, ensuring consistency and uniformity in the application of the law across all states.

In this context, the supremacy of federal law mandates that state courts cannot choose to ignore or disregard federal statutes; they must apply them. This is crucial for maintaining a cohesive legal framework, particularly in areas such as civil rights, commerce, and healthcare, where federal laws are designed to create uniform standards.

The other choices indicate misunderstandings of the relationship between state and federal law. Federal law does not only prevail in criminal cases, nor do state courts have the authority to overlook federal statutes. Additionally, while state courts may challenge federal laws, they do so in the context of applying or interpreting those laws rather than having the latitude to disregard them entirely. This hierarchical relationship is foundational to the structure of American federalism.