Thomas Jefferson (April 13, 1743 (April 2, 1743 O.S.) – July 4, 1826) was an American Founding Father who was the principal author of the United States Declaration of Independence (1776) and the third President of the United States (1801–1809). At the beginning of the American Revolution, Jefferson served in the Continental Congress, representing Virginia. He then served as a wartime Governor of Virginia (1779–1781). Just after the war ended, from mid-1784 Jefferson served as a diplomat, stationed in Paris, initially as a commissioner to help negotiate commercial treaties. In May 1785, he became the United States Minister to France. He was the first United States Secretary of State (1790–1793) during the administration of President George Washington. Upon resigning his office, with his close friend James Madison he organized the Democratic-Republican Party. Elected Vice-President in 1796, under his opponent John Adams, Jefferson with Madison secretly wrote the Kentucky and Virginia Resolutions, which attempted to nullify the Alien and Sedition Acts and formed the basis of states' rights.

Elected president in what Jefferson called the Revolution of 1800, he oversaw a peaceful transition in power, purchased the vast Louisiana Territory from France (1803), and sent the Lewis and Clark Expedition (1804–1806) to explore the new west. His second term was beset with troubles at home, such as the failed treason trial of his former Vice President Aaron Burr, and escalating trouble with Britain. With Britain at war with Napoleon, he tried aggressive economic warfare against them; however, his embargo laws did more damage to American trade and the economy, and provoked a furious reaction in the Northeast. Jefferson has often been rated in scholarly surveys as one of the greatest U.S. presidents, though since the mid-twentieth century, some historians have increasingly criticized him for his failure to act against domestic slavery.^[1][2]