Alien_and_Sedition_Acts Alien and Sedition Acts were four bills passed in 1798 by the Federalists in the United States Congress, who were waging an undeclared naval war with France, later known as the Quasi-War. They were signed into law by President John Adams. Proponents claimed the acts were designed to protect the United States from alien citizens of enemy powers and to stop seditious attacks from weakening the government.