From Citizendium, the Citizens' Compendium
A naval confrontation between the United States and Great Britain. On June 21, 1807, the USS Chesapeake was set upon by the HMS Leopard in U.S. territorial waters just off Newport News, Virginia. Three Americans were killed and eighteen were wounded. The Chesapeake was stopped, boarded, and four U.S. sailors were taken off in an act of impressment. The British claimed that the four sailors, despite having U.S. papers, were British deserters.
An attack of this nature in the territorial waters of another power is an act of war. Many within U.S. Congress pressed for a declaration of war against Great Britain. U.S. President Thomas Jefferson issued a proclamation ordering all British ships out of American waters. As a broader policy, he advocated a policy of economic coercion which was passed as the Embargo Act of 1807.