Third president of the United States. A Virginian farmer and slaveholder, Jefferson served as the first secretary of state under George Washington. He was the principal author of the Declaration of Independence, drafted in the summer of 1776 during the Second Continental Congress. John Adams later claimed there was "not an idea in it but what had been hackneyed in Congress for two years before". Jefferson himself said its object was "not to find out new principles, or new arguments, never before thought of…but to place before mankind the common sense of the subject" as an "expression of the American mind".
Jefferson argued for states' rights and small government, fearing that centralisation would bring tyranny. He emerged as the most prominent leader of the Republican faction (later renamed the Democrats in the 1820s), opposing Alexander Hamilton's vision of a strong central state. Despite his strict-constructionist principles, he completed the Louisiana Purchase in 1803 using executive power — on Hamiltonian terms.
In 1803 Jefferson purchased the Louisiana Territory from Napoleon Bonaparte's France for $15m ($314m in today's dollars). The tract stretched from the Mississippi river to the Rocky Mountains, encompassing 828,000 square miles — more than 20% of modern America. Jefferson worried the deal might be unconstitutional, since the constitution was silent about buying half a continent.
Jefferson's record on slavery was particularly troubling. Though he professed opposition in principle, he owned more than 600 slaves over his lifetime. He fathered several children with one of his slaves, Sally Hemings — a claim documented by the legal scholar Annette Gordon-Reed and later supported by DNA testing. Jefferson favoured extending slavery into new western states under his theory of "diffusion", arguing that dispersing slaves would reduce their concentration and make emancipation less frightening to slaveholders.
Jefferson defeated the incumbent John Adams in 1800 in what became the first peaceful transfer of power between rival factions in America. An electoral-college tie between Jefferson and fellow Republican Aaron Burr forced the lame-duck Federalist Congress to choose between the two. Hamilton tipped the election to Jefferson by impugning Burr. Jefferson struck a bipartisan note in his inaugural address: "We are all Republicans; we are all Federalists."
Jefferson moulded his Republican Party into what became the most enduring party in American history, renamed the Democrats during the 1820s. Abraham Lincoln described Jefferson with reverence, praising him for having "the coolness, forecast, and capacity to introduce into a merely revolutionary document, an abstract truth, applicable to all men and all times". Martin Luther King Jr quoted the Declaration at the March on Washington in 1963.
Jon Meacham, a biographer of Jefferson who holds the Rogers Chair in the American Presidency at Vanderbilt University, describes the Declaration as having been "written for America's most challenging moments".
To doubt everything or to believe everything are two equally convenient solutions; both dispense with the necessity of reflection.