What does judicial review allow courts to do?

Judicial review empowers courts to declare laws or executive actions unconstitutional, which is a fundamental principle of the U.S. legal system. This mechanism serves as a check on legislative and executive powers, ensuring that no law or action can contradict the Constitution. By examining the constitutionality of legislative acts or executive decisions, courts maintain the rule of law and uphold the rights protected by the Constitution. This function is critical in preserving the balance of power among the branches of government and protecting individual liberties.

In terms of the other options, enforcing laws passed by Congress falls under the executive branch's responsibilities. While courts may interpret the Constitution, judicial review specifically pertains to assessing constitutionality rather than broadly interpreting constitutional principles. Overseeing state laws might involve federal jurisdiction in certain cases, but this does not encapsulate the core purpose of judicial review. Thus, the ability to declare laws or actions unconstitutional directly captures the essence of what judicial review allows courts to do.