(background of the case) - shortly before Thomas Jefferson took office, john Adams had appointed William Marbury to be a justice of the peace. Adams had signed Marbury's commission, but it was never delivered. Marbury sued to force Madison to give him commission.
(also a reason why it was important) - Marbury v. Madison was essential for several reasons. It established the Supreme Court’s power to declare acts of Congress unconstitutional. With doing so, it set the Court as the final authority on the Constitution. This helped make the judicial branch of government similar to the other two branches. Chief Justice John Marshall and later federal judges would use the power of judicial review as a check on the legislative and executive branches.