Thomas Jefferson (April 13, 1743 – July 4, 1826) was the principal author of the Declaration of Independence (1776) and the third President of the United States (1801–1809). He was an influential Founding Father, and an exponent of Jeffersonian democracy. Jefferson envisioned America as a great "Empire of Liberty" that would promote republicanism.
At the beginning of the American Revolution, Jefferson served in the Continental Congress, representing Virginia. He then served as the wartime Governor of Virginia (1779–1781), barely escaping capture by the British in 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, Jefferson advised against a national bank and the Jay Treaty. Upon leaving office, with his close friend James Madison he organized the Democratic-Republican Party to oppose Treasury Secretary Alexander Hamilton's policies, especially his desire to create a national bank. He and 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 he 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. He decided to allow slavery in the acquired territory, which laid the foundation for the crisis of the Union a half century later. 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. Jefferson always distrusted Britain as a threat to American values. With Britain at war with Napoleon, he tried aggressive economic warfare, however his embargo laws stopped American trade, hurt the economy, and provoked a furious reaction in the Northeast.