United States



{{Infobox Country|native_name = United States of America|common_name = the United States|image_flag = Flag of the United States.svg|image_coat = US-GreatSeal-Obverse.svg|length = 1776 - Present|symbol_type = Great Seal|national_motto = "In God We Trust"(since 1956)("From Many, One"; Latin, traditional)]"|languages_type = National language ([de facto)]|latd=38 |latm=53 |latNS=N |longd=77 |longm=02 |longEW=W|largest_city = New York City [constitutional republic|leader_name1 = [George W. Bush Republican Party (United States)|leader_title2 = Vice-President of the United States|leader_name2 = Dick Cheney Republican Party (United States)|leader_title3 = |leader_name3 = Nancy Pelosi Democratic Party (United States)|leader_title4 = Chief Justice of the United States|leader_name4 = John Roberts |established_event1 = [United States Declaration of Independence|established_date1 = July 4 1776|established_date2 = [September 3 1783 ($)|currency_code = USD "$"|country_code = USA|utc_offset = -5 to -10|utc_offset_DST = -4 to -10|cctld = [.us .gov .mil .edu|footnote1 = English is the [de facto language of American government; Spanish language is the second most common. English, Spanish, French language, and Hawaiian language are officially recognized by various states.|footnote2 = Sometimes listed as fourth largest in area; the rank is List of countries and outlying territories by total area with People's Republic of China. The U.S. figure includes only the fifty states and the District of Columbia, not the territories.|footnote3 =The population estimate includes people whose usual residence is in the fifty states and the District of Columbia, including noncitizens. It does not include either those residing in the territories, amounting to more than four million U.S. citizens (most of whom reside in Puerto Rico), or U.S. citizens residing outside the United States.-->The United States of America is a federation constitutional republic comprising U.S. state and a Capital districts and territories. The country is situated almost entirely in the western hemisphere: its forty-eight Continental United States and Washington, D.C., the capital district, lie in central North America between the Pacific and Atlantic Oceans, bordered by Canada–United States border and United States-Mexico border; the state of Alaska is in the northwest of the continent with Canada to its east, and the state of Hawaii is in the mid-Pacific. The United States also possesses Territories of the United States, or insular areas, that are scattered around the Caribbean and Pacific.

At 3.79 million square miles (9.83 million km²) and with over 300 million people, the United States is the List of countries and outlying territories by total area largest country by total area, and third largest by land area and by List of countries by population. The United States is one of the world's most ethnically diverse nations, the product of large-scale immigration to the United States.Adams, J.Q., and Pearlie Strother-Adams (2001). Dealing with Diversity. Chicago: Kendall/Hunt. ISBN 078728145X. Economy of the United States is the largest in the world, with a nominal 2006 gross domestic product (GDP) of more than U.S. dollar13 trillion.

The nation was founded by the thirteen colonies of Kingdom of Great Britain located along the East Coast of the United States. After proclaiming themselves as "states," they issued the United States Declaration of Independence on July 4, 1776. The rebellious states defeated Britain in the American Revolutionary War, the first successful History of colonialism.Dull, Jonathan R. (2003). "Diplomacy of the Revolution, to 1783," p. 352, chap. in A Companion to the American Revolution, ed. Jack P. Greene and J. R. Pole. Maiden, Mass.: Blackwell, pp. 352–361. ISBN 1405116749.

A Philadelphia Convention adopted the current United States Constitution on September 17, 1787; its ratification the following year made the states part of a single republic. The United States Bill of Rights, comprising ten List of amendments to the United States Constitution, was ratified in 1791. In the nineteenth century, the United States acquired land from First French Republic, Spanish Empire, Mexican-American War, and Russian Empire, and annexed the Republic of Texas and the Republic of Hawaii. The American Civil War ended History of slavery in the United States and prevented a permanent split of the country. The Spanish-American War and World War I confirmed its status as a military power. In 1945, the United States emerged from World War II as the Nuclear weapons and the United States and a permanent member of the United Nations Security Council. The sole remaining superpower in the post–Cold War era, the United States is perceived by many as the dominant economic, political, cultural, and military force in the world.

Etymology Common abbreviations of the United States of America include the United States, the U.S., and the U.S.A. Colloquial names for the country include the common America as well as the States. The term Americas#Naming, for the lands of the western hemisphere, was coined in the early sixteenth century after Amerigo Vespucci, an Italian explorer and cartographer. The full name of the country was first used officially in the United States Declaration of Independence, which was the "unanimous Declaration of the thirteen united States of America" adopted by the "Representatives of the united States of America" on July 4, 1776. The current name was finalized on November 15, 1777, when the Second Continental Congress adopted the Articles of Confederation, the first of which states, "The Stile of this Confederacy shall be 'The United States of America.'" Columbia (name), a once popular name for the Americas and the United States, was derived from Christopher Columbus. It appears in the name District of Columbia. A female personification of Columbia appears on some official documents, including certain prints of U.S. currency.

The standard way to demonym of the United States is as an American (word). Though United States is the formal adjective, American and U.S. are the most common adjectives used to refer to the country ("American values," "U.S. forces"). American is rarely used in English to refer to people not connected to the United States.

Geography of the continental United StatesThe United States is the world's third or fourth List of countries and outlying territories by total area, before or after the People's Republic of China, depending on how two territories disputed by China and India are counted. Including only land area, the United States is third in size behind Russia and China, just ahead of Canada. The continental United States stretches from the Atlantic Ocean to the Pacific Ocean and from Canada to Mexico and the Gulf of Mexico. Alaska is the largest state in area. Separated by Canada, it touches the Pacific and Arctic Oceans. Hawaii occupies an archipelago in the Pacific, southwest of North America. The Commonwealth (United States insular area) of Puerto Rico, the largest and most populous U.S. territory, is in the northeastern Caribbean. With a few exceptions, such as the territory of Guam and the westernmost portions of Alaska, nearly all of the country lies in the western hemisphere.

The coastal plain of the Atlantic seaboard gives way further inland to deciduous forests and the rolling hills of the Piedmont (United States). The Appalachian Mountains divide the eastern seaboard from the Great Lakes and the grasslands of the Midwest. The Mississippi River-Missouri River, the world's List of rivers by length, runs mainly north-south through the heart of the country. The flat, fertile prairie land of the Great Plains stretches to the west. The Rocky Mountains, at the western edge of the Great Plains, extend north to south across the continental United States, reaching altitudes higher than 14,000 feet (4,300 m) in Colorado. The area to the west of the Rocky Mountains is dominated by deserts such as the Mojave Desert and the rocky Great Basin. The Sierra Nevada (U.S.) range runs parallel to the Rockies, relatively close to the Pacific coast. At 20,320 ft (6,194 m), Alaska's Mount McKinley is the country's tallest peak. Active volcanoes are common throughout the Alexander Archipelago and Aleutian Islands and the entire state of Hawaii is built upon tropical volcanic islands. The supervolcano underlying Yellowstone National Park in the Rockies is the continent's largest volcanic feature.

Because of the United States' large size and wide range of geographic features, nearly every type of climate is represented. The climate is temperate in most areas, tropical in Hawaii and southern Florida, polar in Alaska, semiarid in the Great Plains west of the 100th meridian west, desert in the Southwest, Mediterranean in coastal California, and arid in the Great Basin. Extreme weather is not uncommon—the states bordering the Gulf of Mexico are prone to hurricanes and most of the world's tornadoes occur within the continental United States.

Environment , the Bald Eagle has been the national bird of the United States since 1782With habitats ranging from tropical to Arctic, U.S. plant life is very diverse. The country has more than 17,000 identified native species of flora, including 5,000 in California (home to the Sequoia, the Sequoiadendron, and the Bristlecone pine trees in the world). More than 400 mammal, 700 bird, 500 reptile and amphibian, and 90,000 insect species have been documented. Wetlands such as the Florida Everglades are the base for much of this diversity. The country's ecosystems include thousands of nonnative exotic species that often harm indigenous plant and animal communities. The Endangered Species Act of 1973 protects threatened species and United States Fish and Wildlife Service list of endangered species and Protected areas of the United States, which are monitored by the U.S. Fish and Wildlife Service.

In 1872, the world's first national park was established at Yellowstone. Another fifty-seven national parks and hundreds of other federally managed parks and forests have since been formed. Wilderness areas have been established around the country to ensure long-term protection of pristine habitats. Altogether, the U.S. government regulates 1,020,779 square miles (2,643,807 km²), 28.8 percent of the country's total land area. Protected parks and forestland constitute most of this. As of March 2004, approximately 16 percent of public land under Bureau of Land Management administration was being leased for commercial oil and natural gas drilling; public land is also leased for mining and cattle ranching. The United States is the second largest emitter, Environment of China, of carbon dioxide from the burning of fossil fuels. The energy policy of the United States is widely debated; many call on the country to take a leading role in fighting global warming.

History Native Americans and European settlers The Indigenous peoples of the Americas of the U.S. mainland, including Alaska Natives, Models of migration to the New World. They began arriving at least 12,000 and as many as 40,000 years ago. Several indigenous communities in the pre-Columbian era developed advanced agriculture, grand architecture, and state-level societies. European explorer Christopher Columbus arrived at Puerto Rico on November 19, 1493, making First contact (anthropology) with the Native Americans. In the years that followed, the majority of the Native American population was killed by epidemics of Eurasian diseases.Mann, Charles C. (2005). 1491: New Revelations of the Americas Before Columbus. New York: Knopf. ISBN 140004006X.

transported Pilgrims to the New World in 1620, as depicted in William Halsall's The Mayflower in Plymouth Harbor, 1882Spaniards established the earliest European colonies on the mainland, in the area they named Florida; of these, only St. Augustine, Florida, founded in 1565, remains. Later Spanish settlements in the present-day southwestern United States drew thousands through Mexico. French fur traders established outposts of New France around the Great Lakes; France eventually claimed much of the North American interior as far south as the Gulf of Mexico. The first successful British settlements were the Virginia Colony in Jamestown, Virginia in 1607 and the Pilgrims' Plymouth Colony in 1620. The 1628 chartering of the Massachusetts Bay Colony resulted in a wave of migration; by 1634, New England had been settled by some 10,000 Puritans. Between the late 1610s and the revolution, the British shipped an estimated 50,000 convicts to its American colonies. Beginning in 1614, the Dutch established settlements along the lower Hudson River, including New Amsterdam on Manhattan Island. The small settlement of New Sweden, founded along the Delaware River in 1638, was taken over by the Dutch in 1655.

In the French and Indian War, the colonial extension of the Seven Years War, Britain seized Canada from the French, but the francophone population remained politically isolated from the southern colonies. By 1674, the British had won the former Dutch colonies in the Anglo-Dutch Wars; the province of New Netherland was renamed New York. With the 1729 division of the Carolinas and the 1732 colonization of Georgia (U.S. state), the thirteen British colonies that would become the United States of America were established. All had active local and colonial governments with elections open to most free men, with a growing devotion to the ancient rights of Englishmen and a sense of self government that stimulated support for republicanism. All had legalized the African slave trade. With high birth rates, low death rates, and steady immigration, the colonies doubled in population every twenty-five years. The Christian Revivalism movement of the 1730s and 1740s known as the First Great Awakening fueled interest in both religion and religious liberty. By 1770, the colonies had an increasingly Anglicisation population of three million, approximately half that of Britain itself. Though No taxation without representation, they were given no representation in the Parliament of Great Britain.

Independence and expansion , by John Trumbull, 1817–18Tensions between Thirteen Colonies and the British during the American Revolution of the 1760s and early 1770s led to the American Revolutionary War, fought from 1775 through 1781. On June 14, 1775, the Second Continental Congress, convening in Philadelphia, established a Continental Army under the command of George Washington. Proclaiming that "all men are created equal" and endowed with "certain inalienable rights," the Congress adopted the United States Declaration of Independence, drafted largely by Thomas Jefferson, on July 4, 1776. In 1777, the Articles of Confederation were adopted, uniting the states under a weak federal government that operated until 1788. Some 70,000–80,000 Loyalist (American Revolution)s to the British Crown fled the rebellious states, many to Nova Scotia and the new Canada under British Imperial control (1764-1867). Native Americans, with divided allegiances, fought on both sides of Western theater of the American Revolutionary War. of the United States ConstitutionAfter the Siege of Yorktown by American forces, who were France in the American Revolutionary War, Great Britain Treaty of Paris (1783) of the thirteen states in 1783. A Philadelphia Convention was organized in 1787 by those who wished to establish a strong national government with power over the states. By June 1788, nine states had ratified the United States Constitution, sufficient to establish the new government; the republic's 1st United States Congress, and President of the United States, George Washington, took office in 1789. New York City was the federal capital for a year, before the government relocated to Philadelphia. In 1791, the states ratified the United States Bill of Rights, ten amendments to the Constitution forbidding federal restriction of personal freedoms and guaranteeing a range of legal protections. Attitudes toward History of slavery in the United States were shifting; a Article One of the United States Constitution#Section 9: Limits on Congress protected the African slave trade only until 1808. The Northern states abolished slavery between 1780 and 1804, leaving the slave states of the South as defenders of the "peculiar institution." In 1800, the federal government moved to the newly founded History of Washington, D.C. The Second Great Awakening made evangelicalism a force behind various social reform movements.Americans' eagerness to Territorial acquisitions of the United States began a cycle of Indian Wars that stretched to the end of the nineteenth century, as Native Americans were stripped of their land. The Louisiana Purchase of French-claimed territory under President Thomas Jefferson in 1803 virtually doubled the nation's size. The War of 1812, declared against Britain over various grievances and fought to a draw, strengthened American nationalism. A series of U.S. military incursions into Florida led Spanish Cession it and other Gulf Coast territory in 1819. The country annexed the Republic of Texas in 1845. The concept of Manifest Destiny was popularized during this time.Morrison, Michael A. (1999). Slavery and the American West: The Eclipse of Manifest Destiny and the Coming of the Civil War. Chapel Hill: University of North Carolina Press, pp. 13–21. ISBN 0807847968. The 1846 Oregon Treaty with Britain led to U.S. control of the present-day Northwestern United States. The U.S. victory in the Mexican-American War resulted in the 1848 Mexican Cession of California and much of the present-day Southwestern United States. The California Gold Rush of 1848–1849 further spurred western migration. Rail transport in the United States#History made relocation much less arduous for settlers and increased conflicts with Native Americans. Over a half-century, up to 40 million American bison, commonly called buffalo, were slaughtered for skins and meat and to ease the railways' spread. The loss of the bison, a primary economic resource for the plains Indians, was an existential blow to many native cultures.

Civil War and industrialization , lithograph by Currier & Ives, ca. 1863Origins of the American Civil War between slave and Free state (USA)s mounted with increasing disagreements over the relationship between the states' rights and Bleeding Kansas over the expansion of slavery into new states. Abraham Lincoln, candidate of the largely antislavery Republican Party (United States), was elected president in 1860. Before he took office, seven slave states declared their secession from the United States, forming the Confederate States of America. The federal government maintained secession was illegal, and with the Confederate Battle of Fort Sumter, the American Civil War began and four more slave states joined the Confederacy. The Union (American Civil War) Emancipation Proclamation as its Union Army advanced through the South. Following the Union victory in 1865, three amendments to the U.S. Constitution Thirteenth Amendment to the United States Constitution, Page 7 lists a total slave population of 3,953,760. Fourteenth Amendment to the United States Constitution, and Fifteenth Amendment to the United States Constitution. The war and its resolution led to a substantial increase in federal power.De Rosa, Marshall L. (1997). The Politics of Dissolution: The Quest for a National Identity and the American Civil War. Edison, NJ: Transaction, p. 266. ISBN 1560003499.

, New York City, 1902After the war, the Abraham Lincoln assassination Radical Republican Reconstruction policies aimed at reintegrating and rebuilding the Southern states while ensuring the rights of the newly freed slaves. The disputed United States presidential election, 1876 resolved by the Compromise of 1877 ended Reconstruction; Jim Crow laws soon Disfranchisement after the Civil War. In the North, urbanization and an unprecedented Immigration to the United States#Immigration 1850 to 1930 hastened the United States technological and industrial history#Technological systems and infrastructure. The wave of immigration, which lasted until 1929, provided labor for U.S. businesses and transformed American culture. High tariff protections, national infrastructure building, and new banking regulations encouraged industrial growth. The 1867 Alaska purchase from Russia completed the country's mainland expansion. The Wounded Knee massacre in 1890 was the last major armed conflict of the Indian Wars. In 1893, the Ancient Hawaii of the Pacific Kingdom of Hawaii was overthrown in a coup led by American residents; the archipelago was annexed by the United States in 1898. Victory in the Spanish-American War that same year demonstrated that the United States was a Great power and resulted in the annexation of Puerto Rico and the Philippines.Spielvogel, Jackson J. (2005). Western Civilization: Volume II: Since 1500. Belmont, CA: Wadsworth, p. 708. ISBN 0534646042. The Philippines gained independence a half-century later; Puerto Rico remains a Commonwealth (United States insular area) of the United States.

World War I, Great Depression, and World War II , 1936At the outbreak of World War I in 1914, the United States remained neutral. Americans sympathized with the British and French, although many citizens, mostly Irish and German, opposed intervention.Foner, Eric, and John A. Garraty (1991). The Reader's Companion to American History. New York: Houghton Mifflin, p. 576. ISBN 0395513723. In 1917, the United States joined the Allies of World War I, turning the tide against the Central Powers. Reluctant to be involved in European affairs, the Senate did not ratify the Treaty of Versailles, which established the League of Nations. The country pursued a policy of unilateralism, verging on isolationism.McDuffie, Jerome, Gary Wayne Piggrem, and Steven E. Woodworth (2005). U.S. History Super Review. Piscataway, NJ: Research & Education Association, p. 418. ISBN 0738600709. In 1920, the women's rights movement won passage of a Nineteenth Amendment to the United States Constitution granting History of women's suffrage in the United States. In part due to the service of many in the war, Native Americans gained United States nationality law in the Indian Citizenship Act of 1924.

During Roaring Twenties, the United States enjoyed a period of unbalanced prosperity as farm profits fell while industrial profits grew. A rise in debt and an inflated stock market culminated in the Wall Street Crash of 1929 that triggered the Great Depression. After his election as president in 1932, Franklin Delano Roosevelt responded with the New Deal, a range of policies increasing government intervention in the economy. The Dust Bowl of the mid-1930s impoverished many farming communities and spurred a new wave of western migration. The nation would not fully recover from the economic depression until the industrial mobilization spurred by its entrance into World War II. The United States, effectively neutral during the war's early stages after the Invasion of Poland (1939) in September 1939, began supplying materiel to the Allies of World War II in March 1941 through the Lend-Lease program.

On December 7, 1941, the United States joined the Allies against the Axis Powers after a surprise attack on Pearl Harbor by Japan. World War II cost far more money than any other war in American history, but it boosted the economy by providing capital investment and jobs, while bringing many women into the labor market. Allied conferences at United Nations Monetary and Financial Conference and Yalta Conference outlined a new system of intergovernmental organizations that placed the United States and the United Nations and Soviet Union and the United Nations at the center of world affairs. As Victory in Europe Day, a 1945 United Nations Conference on International Organization held in San Francisco produced the United Nations Charter, which became active after the war. The United States, having Manhattan Project, used them on the Japanese cities of atomic bombings of Hiroshima and Nagasaki in August. surrender of Japan on September 2, ending the war.Pacific War Research Society (2006). Japan's Longest Day. New York: Oxford University Press. ISBN 4770028873.

Superpower delivering his "I Have a Dream" speech, 1963The United States and Soviet Union jockeyed for power after World War II during the Cold War, dominating the military affairs of Europe through the North Atlantic Treaty Organization and the Warsaw Pact. The United States promoted liberal democracy and capitalism, while the Soviet Union promoted communism and a centrally planned economy. The Soviet Union supported dictatorships, as did the United States on occasion, and both engaged in proxy wars. United States troops fought People's Republic of China forces in the Korean War of 1950–53. The House Committee on Un-American Activities pursued a series of investigations into suspected leftist subversion, while Senator Joseph McCarthy became the figurehead of anticommunist sentiment.

The Soviet Union launched the first manned spacecraft in 1961, prompting U.S. efforts to raise proficiency in mathematics and science and President John F. Kennedy's call for the country to be first to land "a man on the moon," achieved in 1969.Rudolph, John L. (2002). Scientists in the Classroom: The Cold War Reconstruction of American Science Education. New York: Palgrave Macmillan, p. 1. ISBN 0312295715. Kennedy also faced a Cuban Missile Crisis with Soviet forces in Cuba. Meanwhile, America experienced sustained economic expansion. A growing American Civil Rights Movement (1955-1968) headed by prominent African Americans, such as Martin Luther King Jr., fought segregation and discrimination, leading to the abolition of Jim Crow laws and passage of the Civil Rights Act of 1964.Klarman, Michael J. (2006). From Jim Crow to Civil Rights: The Supreme Court and the Struggle for Racial Equality. New York: Oxford University Press, p. 552. ISBN 0195310187. Following John F. Kennedy assassination in 1963, his successors expanded a proxy war in Southeast Asia into the unsuccessful Vietnam War.

(1981–89) challenges Soviet general secretary Mikhail Gorbachev to Tear down this wall the Berlin Wall, 1987As a result of the Watergate scandal, in 1974 Richard Nixon became the first U.S. president to resign, rather than be impeachment on charges including obstruction of justice and abuse of power. The election of Ronald Reagan as president in 1980 marked a significant Conservatism in the United States#Nixon, Reagan, and Bush. In the late 1980s and 1990s, the History of the Soviet Union (1985-1991), leading to its collapse. The leadership role taken by the United States and its allies in the United Nations–sanctioned Gulf War and the Yugoslav wars helped to preserve its position as the world's last remaining superpower. The longest economic expansion in modern U.S. history—from March 1991 to March 2001—encompassed the administration of President Bill Clinton. In 1998, Clinton was Impeachment of Bill Clinton on charges relating to a Paula Jones and a Lewinsky scandal, but was acquitted by the Senate and remained in office.

The controversial United States presidential election, 2000 was resolved by a Bush v. Gore that effectively awarded the presidency to Texas Governor#United States George W. Bush. September 11, 2001 attacks, terrorists struck the World Trade Center in New York City and The Pentagon near Washington, D.C., killing nearly three thousand people. In the aftermath, President Bush launched the War on Terrorism under a military philosophy stressing preemptive war now known as the Bush Doctrine. In late 2001, U.S. forces led a NATO War in Afghanistan (2001–present), removing the Taliban government and al-Qaeda terrorist training camps. Taliban insurgents continue to fight a guerilla war against the NATO-led force. In 2002, the Bush administration began to press for regime change in Iraq on Rationale for the Iraq War. Lacking the support of NATO, Bush formed a Coalition of the Willing and the U.S. 2003 invasion of Iraq in 2003, removing President Saddam Hussein from power. Although facing both external and internal pressure to withdraw, the United States maintains its Post-invasion Iraq, 2003–present.

Government and politics , which houses the United States CongressThe United States is the world's oldest surviving federation. It is a constitutional republic, "in which majority rule is tempered by minority rights protected by law."Scheb, John M., and John M. Scheb II (2002). An Introduction to the American Legal System. Florence, KY: Delmar, p. 6. ISBN 0766827593. It is fundamentally structured as a representative democracy, though U.S. citizens residing in the territories are excluded from voting for federal officials.Raskin, James B. (2003). Overruling Democracy: The Supreme Court Vs. the American People. London and New York: Routledge, pp. 36–38. ISBN 0415934397. The government is regulated by a system of checks and balances defined by the United States Constitution, which serves as the country's supreme legal document and as a social contract for the people of the United States. In the Federalism#United States, citizens are usually subject to Political divisions of the United States, federal, state, and local; the Local government in the United States's duties are commonly split between County (United States) and municipal governments. In almost all cases, executive and legislative officials are Elections in the United States by a plurality voting system of citizens by district. There is no proportional representation at the federal level, and it is very rare at lower levels. Federal and state judicial and cabinet officials are typically nominated by the executive branch and approved by the legislature, although some state judges are elected by popular vote. The Twenty-sixth Amendment to the United States Constitution and voter registration is the individual's responsibility; there are no mandatory voting laws.

, home and work place of the U.S. presidentThe federal government is composed of three branches:





The House of Representatives has 435 members, each representing a congressional district for a two-year term. House seats are United States Congressional apportionment among the fifty states by population every tenth year. As of the United States Census, 2000, seven states have the minimum of one representative, while California, the most populous state, has fifty-three. Each state has two senators, elected at-large to six-year terms; one third of Senate seats are up for election every second year. The president serves a four-year term and may be elected to the office Term limits in the United States. The president is United States presidential election, but by an indirect United States Electoral College system in which the determining votes are apportioned by state. The Supreme Court, led by the Chief Justice of the United States, has nine members, who serve for life.All laws and procedures of both state and federal governments are subject to review, and any law ruled in violation of the Constitution by the judicial branch is overturned. The original text of the Constitution establishes the structure and responsibilities of the federal government, the relationship between it and the individual states, and essential matters of military and economic authority. Article One of the United States Constitution protects the right to the "great writ" of Habeas corpus in the United States, and Article Three of the United States Constitution guarantees the Jury trial#The United States in all criminal cases. Article Five of the United States Constitution require the approval of three-fourths of the states. The Constitution has been amended twenty-seven times; the first ten amendments, which make up the United States Bill of Rights, and the Fourteenth Amendment to the United States Constitution form the central basis of individual rights in the United States.

Politics in the United States have operated under a two-party system for virtually all of the country's history. For elective offices at all levels, state-administered primary elections are held to choose the major party nominees for subsequent general elections. Since the United States presidential election, 1856, the two dominant parties have been the Democratic Party of the United States, History of the United States Democratic Party (though its Democratic-Republican Party), and the Republican Party of the United States, History of the United States Republican Party. The current president, George W. Bush, is a Republican; following the United States general elections, 2006, the Democratic Party controls both the House and the Senate. The Senate has two Independent (politician) members—one is a former Democratic incumbent, the other is a self-described socialist; every member of the House is a Democrat or Republican. An overwhelming majority of state and local officials are also either Democrats or Republicans. Since the Civil War, only one Third party (United States) presidential candidate—former president Theodore Roosevelt, running as a Progressive Party (United States, 1912) in United States presidential election, 1912—has won as much as 20 percent of the popular vote.

Within American political culture, the Republican Party is considered "center-right" or Conservatism in the United States and the Democratic Party is considered "center-left" or Liberalism in the United States, but members of both parties have a wide range of views. In an August 2007 poll, 36 percent of Americans described themselves as "conservative," 34 percent as "moderate," and 25 percent as "liberal." On the other hand, a plurality of adults, 35.9 percent, identify as Democrats, 32.9 percent as independents, and 31.3 percent as Republicans. The states of the Northeast, Great Lakes, and the West Coast (U.S.) are relatively liberal-leaning—they are known in political parlance as "Red states and blue states." The "red states" of the South and the Rocky Mountains lean conservative.

Foreign relations and military George W. Bush (right) with Prime Minister of the United Kingdom Gordon BrownThe United States has vast economic, political, and military influence on a global scale, which makes its foreign policy a subject of great interest around the world. Almost all countries have List of Washington, D.C. embassies in Washington, D.C., and many host Consul (representative) around the country. Likewise, nearly all nations host American diplomatic missions. However, Cuba-United States relations, U.S.-Iran relations, U.S.-North Korea relations, Bhutan, and Sudan do not have formal diplomatic relations with the United States.

American isolationists have often been at odds with internationalists, as anti-imperialists have been with promoters of Manifest Destiny and American Empire. American Philippine-American War drew sharp rebukes from Mark Twain, philosopher William James, and many others. Later, President Woodrow Wilson played a key role in creating the League of Nations, but the Senate prohibited American membership in it. Isolationism became a thing of the past when the United States took a lead role in founding the United States and the United Nations, becoming a permanent member of the United Nations Security Council and host to the United Nations headquarters. The United States enjoys a special relationship with Anglo-American relations and strong ties with United States-Australia relations, New Zealand-United States relations, Japanese-American relations, Israel-United States relations, and fellow NATO members. It also works closely with its neighbors through the Organization of American States and free trade agreements such as the trilateral North American Free Trade Agreement with Canada-United States relations and United States-Mexico relations. In 2005, the United States spent $27.3 billion on official development assistance, the most in the world; however, as a share of gross national income (GNI), the U.S. contribution of 0.22 percent ranked twentieth of twenty-two donor states. On the other hand, nongovernmental sources such as private foundations, corporations, and educational and religious institutions donated $95.5 billion. The total of $122.8 billion is again the most in the world and seventh in terms of GNI percentage.

aircraft carrierThe president holds the title of commander-in-chief of the nation's armed forces and appoints its leaders, the United States Secretary of Defense and the Joint Chiefs of Staff. The United States Department of Defense administers the armed forces, including the United States Army, the United States Navy, the United States Marine Corps, and the United States Air Force. The United States Coast Guard falls under the jurisdiction of the United States Department of Homeland Security in peacetime and the United States Department of the Navy in times of war. In 2005, the military had 1.38 million personnel on active duty, along with several hundred thousand each in the Reserve Component of the Armed Forces of the United States and the United States National Guard for a total of of countries by number of