Answer:
Marbury v. Madison was a landmark case decided by the United States Supreme Court in 1803. The case revolved around the issue of whether or not the Supreme Court had the power to declare an act of Congress unconstitutional.
The background of the case was that in the final days of President John Adams' administration, he had appointed a number of new judges, including William Marbury, to fill vacancies in the federal court system. However, when President Thomas Jefferson took office, his Secretary of State, James Madison, refused to deliver the commissions that would have officially appointed Marbury and the other judges. Marbury then sued Madison, asking the Supreme Court to order him to deliver the commission.
The Supreme Court's decision in the case was significant because it established the principle of judicial review, which means that the Supreme Court has the power to declare acts of Congress unconstitutional if they are in conflict with the Constitution. Chief Justice John Marshall, writing for the Court, found that the law that gave the Court the power to hear Marbury's case was itself unconstitutional, and therefore the Court could not order Madison to deliver the commission.
The significance of the decision was that it established the Supreme Court as the final arbiter of the Constitution and the laws of the United States. This decision gave the judicial branch a new and important role in interpreting the Constitution and the laws passed by Congress. It also established the principle of separation of powers, which means that the three branches of government - legislative, executive, and judicial - have separate and distinct powers and responsibilities; so, each branch serves as a check on the others to prevent any one branch from becoming too powerful.