On July 4, 1776, the Second Continental Congress adopted the Declaration of Independence, primarily authored by Thomas Jefferson, proclaiming the colonies' separation from Britain on the principle that all men are created equal with unalienable rights to life, liberty, and the pursuit of happiness. George Washington commanded the Continental Army through years of hardship, with the American cause receiving a decisive boost from the 1777 Battle of Saratoga, which convinced France to enter the war as a crucial ally. The conflict finally ended with the Treaty of Paris in 1783, in which Britain recognized American independence and ceded territory stretching from the Atlantic to the Mississippi River, roughly doubling the new nation's size.
Under the Articles of Confederation, the first governing document, the young United States struggled with a central government too weak to tax, regulate trade, or enforce its laws. In 1787, delegates gathered in Philadelphia not merely to revise the Articles but to draft an entirely new framework. The resulting U.S. Constitution, ratified in 1788, established a federal system with executive, legislative, and judicial branches, separation of powers, and checks and balances, making it the oldest written national constitution still in effect. The Convention produced two key compromises: the Great Compromise, which created a bicameral legislature with equal state representation in the Senate and population-based representation in the House; and the Three-Fifths Compromise, which counted enslaved persons as three-fifths of a person for representation and taxation, granting slaveholding states disproportionate political power in a moral failing of the founding document. To address concerns about federal overreach, the first ten amendments, known as the Bill of Rights, were added in 1791, guaranteeing fundamental freedoms including the First Amendment's protections for religion, speech, press, assembly, and petition. Alexander Hamilton, the first Secretary of the Treasury, then built the national bank and a federal credit system, championing an industrial vision that competed with Jefferson's agrarian ideal.