In 1776, in Philadelphia, the Second Continental Congress declared the independence of the colonies as the “United States”. Led by General George Washington, it won the Revolutionary War. The peace treaty of 1783 established the borders of the new nation. The Articles of Confederation established a central government, but it was ineffectual at providing stability as it could not collect taxes and had no executive officer. A convention wrote a new Constitution that was adopted in 1789 and a Bill of Rights was added in 1791 to guarantee inalienable rights. With Washington as the first president and Alexander Hamilton his chief adviser, a strong central government was created. Purchase of the Louisiana Territory from France in 1803 doubled the size of the United States.Encouraged by the notion of manifest destiny, the United States expanded to the Pacific Coast. While the nation was large in terms of area, its population in 1790 was only 4 million. Westward expansion was driven by a quest for inexpensive land for yeoman farmers and slave owners. The expansion of slavery was increasingly controversial and fueled political and constitutional battles, which were resolved by compromises. Slavery was abolished in all states north of the Mason–Dixon line by 1804, but the South continued the institution, to support the kinds of large scale agriculture that dominated the southern economy. The division of the country along these lines formed the major political issue of the first eight decades of the growth of the United States. Precipitated by the election of Abraham Lincoln as president in 1860, the Civil War began as the southern states seceded from the Union to form their own pro-slavery country, the Confederate States of America. The defeat of the Confederates in 1865 led to the abolition of slavery. In the Reconstruction era following the war, legal and voting rights were extended to freed slaves. The national government emerged much stronger, and gained explicit duty to protect individual rights. However, when white southerners regained their power in the South in 1877, often by paramilitary suppression of voting, they passed Jim Crow laws to maintain white supremacy, as well as new state constitutions that legalized discrimination based on race and prevented most African Americans from participating in public life.