Final answer:
Section 13 of the Judiciary Act of 1789 was declared unconstitutional because it expanded the Supreme Court's original jurisdiction beyond that defined in Article III of the Constitution, which can only be altered via a constitutional amendment. The principle of judicial review was established through Marbury v. Madison, asserting the Supreme Court's power to declare legislative acts unconstitutional.
Step-by-step explanation:
Section 13 of the Judiciary Act of 1789 was declared unconstitutional in the renowned Supreme Court case Marbury v. Madison. The case established the principle of judicial review, which allows the Supreme Court to invalidate laws that are in conflict with the Constitution. The issue arose when the outgoing President John Adams appointed many Federalist judges to secure his party's control over the judiciary. Although the Senate confirmed the appointments, not all the commissions were delivered before Adams left office, and the incoming President Thomas Jefferson instructed his Secretary of State, James Madison, not to deliver them.
William Marbury, whose commission was undelivered, petitioned the Supreme Court for a writ of mandamus to compel Madison to deliver the commission. The Supreme Court, under Chief Justice John Marshall, found that while Marbury had a right to the commission, the section of the Judiciary Act that gave the Supreme Court the power to issue writs of mandamus in cases of original jurisdiction was unconstitutional. The Constitution's Article III defines the extent of the Supreme Court's original jurisdiction, and any change to it required a constitutional amendment, not merely a legislative act such as the Judiciary Act.