Marbury v. Madison was a landmark Supreme Court case that established the principle of judicial review in the United States. The case arose when William Marbury, who had been appointed to a justice of the peace position by President John Adams, sued Secretary of State James Madison for failing to deliver his commission. Marbury argued that he was entitled to receive it under an act passed by Congress and signed into law by Adams shortly before leaving office. In its ruling, the Supreme Court held that while Marbury was indeed entitled to receive his commission, they could not order Madison to do so because part of the Act granting him this right violated Article III of the Constitution which gave original jurisdiction over such cases only to courts created under federal law rather than those created through acts passed by Congress alone. This decision set forth an important precedent whereby if any laws were found unconstitutional then they would be struck down as invalid regardless whether or not they had been enacted with proper authority or procedure; thus establishing judicial review in America's legal system for future generations

In Marbury v. Madison, the Supreme Court ruled that a portion of the Judiciary Act of 1789 was unconstitutional and could not be enforced. Chief Justice John Marshall wrote in his dissenting opinion that Congress had acted within its constitutional authority when it passed the act, which gave original jurisdiction to the Supreme Court to issue writs of mandamus in certain cases. He argued that if any part of an act is unconstitutional, then all parts must be declared void; otherwise, there would be no way for courts to determine what laws are valid or invalid without judicial review. Furthermore, he stated that while Congress may have exceeded its power by passing this law, it did not follow from this fact alone that they had violated their oaths as members of Congress since they were acting on behalf of their constituents who elected them into office. Finally, Marshall concluded by stating that even though some might disagree with him on this point due to political considerations or personal opinions about how government should operate constitutionally speaking; nevertheless he believed firmly in upholding both congressional powers and judicial review as essential components for maintaining a strong federal government under our Constitution's framework