Alien and Sedition Acts, 1798, four laws enacted by the Federalist-controlled U.S. Congress, allegedly in response to the hostile actions of the French Revolutionary government on the seas and in the councils of diplomacy (see XYZ Affair), but actually designed to destroy Thomas Jefferson's Republican party, which had openly expressed its sympathies for the French Revolutionaries. Depending on recent arrivals from Europe for much of their voting strength, the Republicans were adversely affected by the Naturalization Act, which postponed citizenship, and thus voting privileges, until the completion of 14 (rather than 5) years of residence, and by the Alien Act and the Alien Enemies Act, which gave the President the power to imprison or deport aliens suspected of activities posing a threat to the national government. President John Adams made no use of the alien acts. Most controversial, however, was the Sedition Act, devised to silence Republican criticism of the Federalists. Its broad proscription of spoken or written criticism of the government, the Congress, or the President virtually nullified the First Amendment freedoms of speech and the press. Prominent Jeffersonians, most of them journalists, such as John Daly Burk, James T. Callender, Thomas Cooper, William Duane (1760-1835), and Matthew Lyon were tried, and some were convicted, in sedition proceedings. The Alien and Sedition Acts provoked the Kentucky and Virginia Resolutions and did much to unify the Republican party and to foster Republican victory in the election of 1800. The Republican-controlled Congress repealed the Naturalization Act in 1802; the others were allowed to expire (1800-1801).

Four laws passed by the U.S. Congress in 1798, in anticipation of war with France. The acts, precipitated by the XYZ Affair, restricted aliens and curtailed press criticism of the government. Aimed at French and Irish immigrants (who were mostly pro-France), they increased the waiting period for naturalization and authorized expulsion of aliens considered dangerous. The Alien and Sedition Acts were opposed by Thomas Jefferson and others and helped propel Jefferson to the presidency. They were repealed or had expired by 1802.

Learn more about Alien and Sedition Acts with a free trial on Britannica.com.