The USA is the world’s foremost economic and military power, with global interests and an unmatched global reach.
America’s gross domestic product accounts for close to a quarter of the world total, and its military budget is reckoned to be almost as much as the rest of the world’s defence spending put together.
The country is also a major source of entertainment: American TV, Hollywood films, jazz, blues, rock and rap music are primary ingredients in global popular culture.
The United States originated in a revolution which separated it from the British Crown. The constitution, drafted in 1787, established a federal system with a division of powers which has remained unchanged in form since its inception.
President: Barack Obama
Barack Obama, a Democrat and America’s first black president, was elected in 2008, winning for a second term in 2012.
The worst economic crisis in the US since the Great Depression of the 1930s dominated much of Mr Obama’s first term, as did efforts to push through healthcare reform.
He has faced fierce opposition to his agenda from the conservative Republican Party, who have controlled the House of Representatives since 2011, and the powerful Senate since 2015.
In world affairs, his focus has been on scaling down US military involvement in Afghanistan and the Middle East, and “pivoting” foreign and defence policy towards Asia and a rising China.
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The US has the most highly-developed mass media in the world. Its dramas, comedies, soap operas, animations, music videos and films have a global audience and are part of the staple fare of broadcasters worldwide.
Freedom of expression is guaranteed by the constitution, and some broadcast outlets give airtime to extreme hues of political – often right-wing – and religious thinking.
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1565 – First permanent European settlement in North America.
17th-18th centuries – Hundreds of thousands of Africans brought over and sold into slavery to work on cotton and tobacco plantations.
1775 – American Revolution: George Washington leads colonist Continental Army to fight against British rule.
1787 – Founding Fathers draw up new constitution for United States of America. Constitution comes into effect in 1788.
19th century – Residual resistance by indigenous people crushed as immigration from Europe assumes mass proportions, with settlers moving westwards.
1861-1865 – US Civil War: Federalist forces defeat the Confederate pro-slavery states in the South. Slavery is abolished under the Thirteenth Amendment.
1929-33 – 13 million people become unemployed after the Wall Street stock market crash of 1929 triggers what becomes known as the Great Depression.
1941 – Japan attacks the US fleet at Pearl Harbour in Hawaii, precipitating the United States’ entry into World War Two.
1954 – Racial segregation in schools becomes unconstitutional; start of campaign of civil disobedience to secure civil rights for Americans of African descent.
2001 11 September – Co-ordinated suicide attacks on various high-profile targets, prompting the US to embark on a ”war on terror” which includes the invasion of Afghanistan and Iraq.
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