- The United States of America is a constitutional federal republic with a strong democratic tradition, situated primarily in North America. It comprises 50 states and one federal district, and has several territories with differing degrees of affiliation. It is also referred to, with varying formality, as the United States, the U.S., the U.S.A., the U.S. of A., America[1], the States, or (poetically) Columbia.
- Since the mid-20th century, following World War II, the United States has emerged as a dominant global influence in economic, political, military, scientific, technological, and cultural affairs. Because of its influence, the U.S. is considered a superpower and, particularly after the Cold War, a hyperpower by some.
- The country celebrates its founding date as July 4, 1776, when the Second Continental Congress-representing thirteen British colonies-adopted the Declaration of Independence that rejected British authority in favor of self-determination.
- The structure of the government was profoundly changed in 1789, when the states replaced the Articles of Confederation with the United States Constitution. The date on which each of the fifty states adopted the Constitution is typically regarded as the date that state "entered the Union" to become part of the United States.
Prehistory
- American history began with the migration of people from Asia across the Bering land bridge some time prior to 12,000 years ago, possibly following large animals that they hunted into the Americas. These Native Americans left evidence of their presence in petroglyphs, burial mounds, and other artifacts. It is estimated that 2-9 million people lived in the territory now occupied by the U.S. before that population was diminished by European contact and the foreign diseases it brought (although both the number of Native Americans originally on the continent and the number who did not survive European immigration are the subject of continued research and thus are open to debate). Some advanced societies were the Anasazi of the southwest, who inhabited Chaco Canyon (and built sandstone buildings with up to 5 floors), and the Woodland Indians, who built Cahokia, located near present-day St. Louis, a city with a population of 40,000 at its peak in AD 1200.
- In 1776, the 13 colonies Declared Independence from Great Britain and formed the United States, the world's first constitutional and democratic federal republic. The American Revolutionary War followed (1775 to 1783).
- The original political structure was a confederation in 1777, ratified in 1781 as the Articles of Confederation. After long debate, this was supplanted in 1789 by the Constitution, which formed a more centralized federal government.
Civil War
From early colonial times, there was a shortage of labor, which encouraged unfree labor, particularly indentured servitude and slavery. By the mid-19th century, a major division over the issue of states' rights and the expansion of slavery came to a head.
The northern states had become opposed to slavery, while the southern states saw it as necessary for the continued success of southern agriculture and wanted it expanded to newer territories in the West. Several federal laws were passed in an attempt to settle the dispute, including the Missouri Compromise and the Compromise of 1850.
The dispute reached a crisis in 1861, when seven southern states seceded 1 from the Union and formed the Confederate States of America, leading to the Civil War. Soon after the war began, four more southern states seceded, and two states had both Union and Confederate governments.
During the war, President Abraham Lincoln issued the Emancipation Proclamation, mandating the freedom of all slaves in states in rebellion. However, full emancipation did not take place until after the end of the war in 1865, the dissolution of the Confederacy, and the Thirteenth Amendment took effect. The Civil War effectively ended the question of a state's right to secede, and is widely accepted as a major turning point after which the federal government became more powerful than state governments