James Madison, Jr. (March 16, 1751 – June 28, 1836) was an American politician and political philosopher who served as the fourth President of the United States (1809–1817) and is considered one of the Founding Fathers of the United States.
He was the principal author of the United States Constitution, and is often called the "Father of the Constitution". In 1788, he wrote over a third of the Federalist Papers, the most influential commentary on the Constitution. The first president to have served in the United States Congress, he was a leader in the 1st United States Congress, drafting many basic laws, and was responsible for the first ten amendments to the Constitution and thus is also known as the "Father of the Bill of Rights". As a political theorist, Madison's most distinctive belief was that the new republic needed checks and balances to protect individual rights from the tyranny of the majority.
As leader in the House of Representatives, Madison worked closely with President George Washington to organize the new federal government. Breaking with Treasury Secretary Alexander Hamilton in 1791, Madison and Thomas Jefferson organized what they called the Republican Party (later called the Democratic-Republican Party) in opposition to key policies of the Federalists, especially the national bank and the Jay Treaty. He secretly co-authored, along with Thomas Jefferson, the Kentucky and Virginia Resolutions in 1798 to protest the Alien and Sedition Acts.
As Jefferson's Secretary of State (1801–1809), Madison supervised the Louisiana Purchase, doubling the nation's size, and sponsored the ill-fated Embargo Act of 1807. As president, he led the poorly prepared nation into the War of 1812 against Great Britain. A series of disasters at the beginning of the war damaged his reputation, but by 1814–15 American forces repulsed major British invasions, the Federalist opposition fell into disarray, and Americans felt triumphant at the end of the war despite its ending in stalemate for both sides. During and after the war, Madison reversed many of his positions. By 1815, he supported the creation of the second National Bank, a strong military, and a high tariff to protect the new factories opened during the war.