On February 24, 1803, the US Supreme Court first ruled a law unconstitutional (Marbury v Madison). From the article:
"Marbury v. Madison establishes judicial review
On February 24, 1803, the Supreme Court, led by Chief Justice John Marshall, decides the landmark case of William Marbury versus James Madison, Secretary of State of the United States and confirms the legal principle of judicial review—the ability of the Supreme Court to limit Congressional power by declaring legislation unconstitutional—in the new nation.
The court ruled that the new president, Thomas Jefferson, via his secretary of state, James Madison, was wrong to prevent William Marbury from taking office as justice of the peace for Washington County in the District of Columbia. However, it also ruled that the court had no jurisdiction in the case and could not force Jefferson and Madison to seat Marbury. The Judiciary Act of 1789 gave the Supreme Court jurisdiction, but the Marshall court ruled the Act of 1789 to be an unconstitutional extension of judiciary power into the realm of the executive.
In writing the decision, John Marshall argued that acts of Congress in conflict with the Constitution are not law and therefore are non-binding to the courts, and that the judiciary’s first responsibility is always to uphold the Constitution. If two laws conflict, Marshall wrote, the court bears responsibility for deciding which law applies in any given case. Thus, Marbury never received his job.
Jefferson and Madison objected to Marbury’s appointment and those of all the so-called “midnight judges” appointed by the previous president, John Adams, after Jefferson was elected but mere hours before he took office. To further aggravate the new Democratic-Republican administration, many of these Federalist judges–although Marbury was not one of them–were taking the bench in new courts formed by the Judiciary Act, which the lame-duck Federalist Congress passed on February 13, 1801, less than a month before Jefferson’s inauguration on March 4.
As part of the “Revolution of 1800,” President Thomas Jefferson and his Democratic-Republican followers launched a series of attacks against the Federalist-controlled courts. The new Democratic-Republican-controlled Congress easily eliminated most of the midnight judges by repealing the Judiciary Act in 1802. They impeached Supreme Court justice Samuel Chase, but acquitted him amidst inner-party squabbles. The Chase acquittal coupled with Marshall’s impeccably argued decision put an end to the Jeffersonian attack."