Which significant legal precedent was established by John Marshall?

The significant legal precedent established by John Marshall is judicial review. This concept emerged from the landmark Supreme Court case Marbury v. Madison in 1803, in which Chief Justice Marshall asserted the power of the Supreme Court to review and invalidate laws and executive actions that were found to be in conflict with the Constitution. This ruling laid the groundwork for the judiciary's role as a check on the legislative and executive branches, reinforcing the principle that the Constitution is the supreme law of the land.

Judicial review has become a fundamental aspect of the American legal system, enabling courts to uphold constitutional governance and protect individual rights. As a result, the power of judicial review has allowed the judiciary to ensure that no law or governmental action can supersede constitutional authority, significantly shaping the balance of power among the branches of government.