When the British successfully evicted the French from North America in 1763, they embarked on a number of policies that the colonials found increasingly onerous. Settlement was prohibited west of the Appalachians and measures were passed to raise revenue in the colonies. These revenue-raising measures and Britain's generally exploitive mercantilist economic policy irked the colonials, who began to band together to oppose and subvert the measures. Britain increased its military presenceto enforce compliance (a presence part of whose cost was exacted from the colonials), and fighting broke out in 1775. The Second Continental Congress, acting for the 13 colonies, declared independence on July 4, 1776, and created. Articles of Confederation to govern the new nation. Victory over the British came in 1783, and the resulting Treaty of Paris established U.S. boundaries, except for Spanish Florida, west to the Mississippi River.
The Articles of Confederation provided a weak central government and proved inadequate to govern the growing nation. A new constitution was created in 1787, ratified in 1788, and took effect in 1789. George Washington was the first president, and his sober and reasoned judgments were instrumental in establishing both the tenor of the country and the precedents of the executive office. Under the new Constitution, the country began to grow almost immediately. By the Louisiana Purchase of 1803, the United States acquired from France the entire western half of the Mississippi River basin, thereby nearly doubling the size of the national territory. The movement into the lands west of the Appalachians thenceforth became a flood. The United States' victory in the Mexican War (1846-48) brought all or part of the future territory of seven more states (including California and Texas) into American hands.
