The United States of America was founded in 1776 from British colonies along the Atlantic Coast of North America. In 1775 frustration with various British crown practices had led to revolt by colonists in Massachusetts. The next year, representatives of thirteen of the British colonies in North America met in Philadelphia and declared their independence in a remarkable document, the Declaration of Independence, primarily authored by Thomas Jefferson. With the help of their French allies they were eventually able to win the American Revolutionary War against Great Britain.
In 1812, the United states entered a second war with the British Empire, known as the War of 1812. It was caused in large part by the British policy of Impressment (the forcible seizure of American seamen for service in the British Navy)and the British blocking of French seaports where Americans desired to carry on trade. Though the British held the upper hand in most engagements, several of the battles entered the American mythos -- including the Battle of New Orleans, when General Andrew Jackson handed the British one of the worst defeats in their history. Ironically, the battle was fought two weeks after the peace Treaty of Ghent, which ended the hostilities, and restored pre-war conditions.
During the 19th century the country expanded greatly, and many new states entered the Union. Two important events were the Louisiana Purchase, where the United States bought from France all of its territories west of the Mississippi River, and the Mexican War, where the United States obtained California, New Mexico (that included part of Arizona, Utah and Nevada) and the recognition of Texas as a state of the union, after American settlers declared independence from Mexico in the 1830s and joined the United States a decade later.
In response to the election of Republican Abraham Lincoln in 1860, most of the Southern states seceded from the Union, forming the Confederate States of America. The American Civil War ensued. U. S. military leadership was mediocre, at first, compared to that of Confederate generals, particularly Robert E. Lee. But the Union government managed to invade the Southern states, and defeat the Confederate army, by means of an overwhelming advantage in materials and number of soldiers, and the gradual appearance of skilled generals like Ulysses S. Grant and William T. Sherman.
The destructiveness of the Union invasion and defeat of the South, followed by exploitive economic policies in the defeated region after the war, caused lasting bitterness among Southerners toward the U.S. government. This failure of the Federal government to effectively reunite the country contributed to the government's failure for many decades to enforce the Civil Rights of the formerly enslaved African-Americans in the South.
During the 20th century the U.S. was involved in two World Wars. Firmly maintaining neutrality when World War I began in 1914, the United States entered the war after the Lusitania, a British ship carrying many American passengers, was sunk by German submarines. With American help, Great Britain, France and Italy won the war, and imposed severe economic penalties on Germany in the Treaty of Versailles. Despite President Woodrow Wilson's calls for agreeable terms, the economic impact of the reparations mandated by the Treaty were severe. The misery they helped produce in Germany helped Adolf Hitler to seize power in Germany in 1933.
Disillusioned by the failure of the war to achieve the high ideals promised by President Woodrow Wilson, the American people chose Isolationism: they turned their attention inward, away from international relations and solely toward domestic affairs.
During most of the 1920s the United States enjoyed a period of unbalanced prosperity: prices for agricultural commodities and wages fell at the end of the war while new industries (radio, movies, automobiles, and chemicals) flourished. The unevenness was also geographic: the standard of living in rural areas fell increasingly behind that of urban and suburban areas which saw dramatic improvements in housing and urban planning. The boom was reflected by the extension of credit to a dangerous degree, including in the Stock Market, which rose to dangerously inflated levels.
In 1920, the manufacture, sale, import and export of alcohol was prohibited by an amendment to the constitution in order to alleviate various social problems. It was enacted through the Volstead Act. Prohibition ended in 1933 by another change to the constitution; it is considered to have been a failure by most: consumption of alcohol did not decrease markedly while organized crime was strengthened. But it did represent the first instance of a constitutional amendment that directly regulated social activity. The 18th Amendment, then, represented the growing strength of the state in the early 20th century.
The Stock Market crash in 1929 and the ensuing economic depression have been endlessly debated, often along ideological lines. The limited amount of reliable economic information suggests that construction and housing stagnated after 1926, joining declines in the agriculture, mining, and petroleum industries. In all of these overproduction dragged down prices and profits. Wages did not rise fast enough to enable consumers to purchase all the new homes and home products available. Foreign trade was constrained by growing protectionism in the industrialized world. The Stock Market Crash drained away remaining consumer confidence and, more importantly, the confidence of financial institutions. They were extremely reluctant to invest. Thus, the economy sank into a severe depression, referred to by Americans as the "Great Depression", marked by punishing levels of unemployment, negligible investment, and falling prices and wages.
In response to the depression, Congress and the Hoover administration enacted a somewhat isolationist Smoot-Hawley tariff and, with its public works acts, tried to fix prices for farmers, and enacted a public works program based on the belief that the federal government was obliged to maintain high employment levels. These efforts were unprecedented, but the Depression overwhelmed them: indices of prices, profits, production, and unemployment worsened.
With millions unemployed, political ferment and discontent greatly increased among the working classes. An unsympathetic or repressive response from the U.S. government might well have sparked a Socialist uprising, but President Franklin D. Roosevelt, elected in 1932, implemented a number of Keynsian programs to aid the poor and unemployed. He skillfully improved the appeal of these programs to the American people, by refusing to label them "Socialist", or even admit that they were. He also contributed to the future stability of the economy by instituting new regulations in business, particularly banking. Over the past twenty years, historians have de-emphasized the "revolutionary" legislation of the Roosevelt administration, seeing instead a logical outgrowth of the Hoover administration.
Despite his skillful use of language to disguise the semi-Socialist nature of these programs, the wealthy and the business interests were profoundly alarmed by Roosevelt's innovations, and staunchly opposed them. But they were unable to prevent them, due to their widespread popularity.
Despite (or because of) these new programs, economic recovery was very slow. The nadir of the Great Depression was in 1933, but the economy showed very little improvement through the end of the decade, and remained grim until it was dramatically reshaped through America's involvement in World War II.
Isolationist sentiment in America had ebbed, but the United States at first declined to enter the war, limiting itself to giving supplies and weapons to Great Britain, China, and the Soviet Union. American feeling changed drastically with the sudden Japanese attack on Pearl Harbor, and the United States quickly joined the British-Soviet alliance against Japan, Fascist Italy, and Nazi Germany, known as the "Axis Alliance". Even with American participation, it took nearly four years to defeat Germany and Japan. Though the Soviet Union suffered far more casualties than its allies, America's active involvement in the war was vital to preventing an eventual Axis victory.
After the second world war, America experienced a period of great economic growth charaterized by the growth of suburban housing, etc. The United States financed the reconstruction of Germany and Japan and eventually turned the former foes into allies.
America entered the so-called Cold War with the Soviet Union to prevent the spread of communist ideology.
The United States remains a popular destination for immigrants because of its economic prosperity and the high degree of freedom its citizens enjoy.