The Midnight Judges were last-minute appointments made by United States President John Adams in 1801 to fill newly created circuit judgeships. The judges were referred to in this term because President Adams is said to have been signing appointments up until the midnight of his last day in office.
In total, President Adams made 58 Federalist judicial appointments. The goal of the appointments was to ensure that the Federalists would still have people in power, even after President Adams left office. President Adams was being replaced by Thomas Jefferson, who belonged to the opposing Democratic Republicans.
After being sworn into office, President Jefferson refused to appoint the Midnight Judges. Instead he instructed his Secretary of State, James Madison not to deliver the commission of appointments. Jefferson also set out to rescind the Judiciary Act that had made the appointments possibly, eventually succeeding with the Judiciary Act of 1802.
Jefferson's actions led to the landmark Marbury vs. Madison case. William Marbury, one of the appointed Midnight Judges, petitioned the Supreme court to force Madison to deliver the appointment documents. However, although the court ruled in agreement that Madison's actions were illegal, it also observed that it did not constitutionally have the power to force Madison to hand over the documents.