By the turn of the 19th century, after only 120 years of independence, the USA had transformed itself from a pioneer colonial economy into an exporter of industrial goods. In less than a century since then it has become the richest and most powerful state the world has ever known - and yet it is still not entirely sure of its role in international affairs.
'America cannot be an ostrich with its head in the sand', declared President Woodrow Wilson in 1917, calling for American involvement in the First World War. Americans took some persuading. Isolationism had been official policy - known as the Monroe Doctrine after James Monroe, President in 1817-25 - and Americans were too busy building their promised land to concern themselves much with foreign affairs, and particularly foreign wars.
The feeling reasserted itself after the First World War - reinforced by the domestic problems of the 1930s depression - and it took Japan's attack on PEARL HARBOR in December 1941 to tip the balance in favor of involvement in the Second. From that moment, however, the USA has, like it or not, been a major world power in the political as well as the economic sense, a fact emphasized when it dropped the first atomic bombs on Japan in August 1945.
Although the USA and USSR were victorious allies in 1945, it was an alliance of convenience that soon turned to enmity. The two giants confronted each other economically, in the arms race, in space, through propaganda, and on numerous secondary battlefields -notably Korea (1950-3) and Vietnam (1964-73). Defeat in Vietnam led to a resurgence of isolationist sentiments, but continuing confrontation with Communism and the growth of international terrorism, culminating in US action against Libya in 1986, made it clear that America was once again being held accountable for the principles - 'life, liberty and the pursuit of happiness' - on which it was founded by the Declaration of Independence on July 4, 1776.
USA AT A GLANCE
Area 9 372 614 km2 (3 618 772 sq miles)
Capital Washington DC
Government Federal republic
Currency Dollar = 100 cents
Language English; many others spoken
Religions Christian (32% Protestant, 22% Roman Catholic, 2% Eastern Orthodox), Jewish (3%), Muslim (1%)
Climate Mainly temperate; variations include subtropical in the south, Mediterranean type in southern California. Mainly hot summers, cold winters in north. Average temperature in Washington DC ranges from -3 to 6°C (27-43°F) in January to 20-31°C (68-88°F) in July
Main primary products Cereals, soya beans, cotton, tobacco, potatoes, citrus fruits, sugar cane, oilseeds, vegetables and soft fruits, timber, livestock, fish; coal, oil and natural gas, iron ore, copper, lead, zinc, gold, silver, molybdenum
Major Industries Iron and steel, chemicals, motor vehicles, aircraft, telecommunications equipment, computers, electronics, textiles, forestry, paper and pulp, mining, fishing
Main exports Machinery, electrical and electronic goods, chemicals, cereals, motor vehicles, aircraft, soya beans, coal, instruments, petroleum products, small metal manufactures, textiles, tobacco, fruit and vegetables
Life expectancy (yrs.) Male 70 Female 77
Next: Yellowstone National Park