Part IV follows the Democratic-Republicans as the prosecutions widen and the question becomes practical as much as constitutional: who gets to decide if the Alien and Sedition Acts are unconstitutional when the federal courts and Congress are controlled by Federalists. With few options left, Jefferson and Madison turn to state power through the Kentucky and Virginia Resolutions, triggering a national debate over the First Amendment, federal authority, and whether states can interpose or nullify federal law. From there, the story shifts into the endgame, with a second stage of enforcement tied to Fries’ Rebellion and Justice Samuel Chase’s aggressive courtroom posture, then a third wave of prosecutions aimed at editors and critics in the run up to the election of 1800, including the sustained campaign against the Aurora and high profile cases like Thomas Cooper and James Callender. The section closes with the Quasi-War ending, the Sedition Act prosecutions stopping and then sunsetting, Jefferson’s victory and pardons, and the longer aftermath in the judiciary, including the Midnight Judges, the impeachment battles, Marbury v. Madison, and how this crisis helped shape a more modern American understanding of freedom of speech and the press.