Thomas Jefferson was an American Founding Father and the third president of the United States from 1801 to 1809. He was the primary author of the Declaration of Independence. Jefferson was the nation's first U.S. secretary of state under George Washington and then the nation's second vice president under John Adams. Jefferson was a leading proponent of democracy, republicanism, and natural rights, and he produced formative documents and decisions at the state, national, and international levels.