In 1803, France and Britain went to war, and both repeatedly warned the United States not to ship arms to the other. Britain acted on these threats in 1806, stopping U.S. ships to inspect cargoes for military aid to France and seizing suspected deserters from the British navy, along with many Americans. Ultimately, 2,500 U.S. sailors were “impressed” (taken by force) by the British, who needed them for their war with France. In retaliation against the impressments of American sailors, Jefferson convinced Congress to pass a nonimportation law banning particular British-made goods.

Jefferson found one event particularly provoking. In June 1807, the American ship Chesapeake, harboring some British deserters, was ordered to stop by the British frigate Leopard. When the Chesapeake refused, the Leopard opened fire, killing three Americans—right at the mouth of the Chesapeake Bay, well within U.S. territory. In response, Congress passed the Embargo Act of 1807, prohibiting U.S. ships from traveling to all foreign ports, a measure that brought a swift halt to all overseas trade carried in American vessels. Though a drastic measure, the embargo was meant to forestall war by forcing concessions from the British through economic pressure.

The Embargo Act of 1807 was a disaster. From 1790 to 1807, U.S. exports had increased fivefold, but the embargo brought commerce to a standstill. In New England, the heart of the shipping industry, unemployment rose. Grain plummeted in value, river traffic halted, tobacco rotted in the South, and cotton went unpicked. Protest petitions flooded Washington. The federal government suffered too, for import duties were a significant source of revenue. The Federalist Party, in danger of fading away after its weak showing in the election of 1804, began to revive.

Secretary of State James Madison was chosen by Republican caucuses—informal political groups that orchestrated the selection of candidates. The Federalist caucuses again chose Pinckney. Madison won, but Pinckney secured 47 electoral votes, nearly half of Madison’s total. Support for the Federalists remained centered in New England, where the shipping industry suffered heavy losses in the embargo. The Republicans still held the balance of power nationwide.