Answer:
William Marbury most likely supported the Judiciary Act of 1789 because it allowed him to take his case to the Supreme Court. The Act established the federal court system and granted the Supreme Court the power of judicial review, which allowed it to declare acts of Congress unconstitutional. Marbury's case involved a political dispute over his appointment as a justice of the peace by outgoing President John Adams, which was not finalized before the end of Adams' term. Marbury believed that he was entitled to the appointment and sued Secretary of State James Madison to force him to deliver the commission. The Judiciary Act of 1789 provided Marbury with the legal basis to bring his case before the Supreme Court and seek a ruling on the constitutionality of Madison's refusal to deliver the commission.