Who decides if a law goes against the Constitution?

The Supreme Court plays a crucial role in interpreting the Constitution and has the authority to determine whether laws are in alignment with it. This process is known as judicial review, which was established in the landmark case Marbury v. Madison in 1803. When a case involving a law that may conflict with the Constitution is brought before the court, the Supreme Court examines the law and its provisions, scrutinizing them against constitutional principles. If the Court finds that a law is unconstitutional, it has the power to invalidate it, effectively ensuring that the Constitution remains the supreme law of the land.

This function of the Supreme Court is foundational to the system of checks and balances established in the United States government, where the legislative and executive branches have their powers regulated by the judiciary. Other branches, such as the President or Congress, do not have the authority to make these determinations regarding constitutionality, thus reinforcing the unique and critical role of the Supreme Court in upholding the principles of constitutional law.