Final answer:
Marbury v. Madison is a landmark Supreme Court decision because it established the principle of judicial review, wherein the Court asserted its power to invalidate legislative or executive actions that conflict with the Constitution. This strengthened the judiciary's role in the government and maintained a balance of power.
Step-by-step explanation:
The historic case of Marbury v. Madison, decided in 1803, is characterized as a landmark decision because it established the principle of judicial review. This principle asserted the power of the Supreme Court to review and potentially nullify the actions of the other branches of government if deemed unconstitutional. The case arose from a conflict at the turn of the 19th century between the outgoing administration of John Adams and the incoming administration of Thomas Jefferson. William Marbury, one of Adams's late appointees, pursued his commission through the Supreme Court after Jefferson's Secretary of State, James Madison, failed to deliver it.
Chief Justice John Marshall's ruling was a strategic masterpiece which simultaneously supported the claims of Marbury, upheld the authority of the Supreme Court without challenging the new President, and established the Court's role as the arbiter of constitutional interpretation via judicial review. The decision reinforced the balance of power among the government's branches and the independence of the judiciary. It is regarded as one of the foundational cases that have shaped the nature of the American constitutional system.
Despite ruling in favor of Marbury on the merits, the Court denied to issue a writ of mandamus, as the Judiciary Act of 1789 which would have allowed the Court to do so, was found unconstitutional. The dual nature of John Marshall's decision limited the Court's direct jurisdiction yet affirmed its overarching constitutional authority.