Under the United States Constitution, the President of the United States is the head of state and head of government of the United States. As chief of the executive branch and head of the federal government as a whole, the presidency is the highest political office in the United States by influence and recognition. The president is also the commander-in-chief of the United States Armed Forces. The president is indirectly elected to a four-year term by an Electoral College (or by the House of Representatives should the Electoral College fail to award an absolute majority of votes to any person). Since the ratification of the Twenty-second Amendment to the United States Constitution in 1951, no person may be elected to the office of President more than twice. Furthermore, no person who served more than two years of a term — to which someone else was elected — may be elected more than once. Upon the death, resignation, or removal from office of an incumbent President, the Vice President assumes the office.

The United States of America (commonly abbreviated to the United States, the U.S., the USA, America, and the States) is a federal constitutional republic comprising fifty states and a federal district. The country is situated mostly in central North America, where its forty-eight contiguous states and Washington, D.C., the capital district, lie between the Pacific and Atlantic Oceans, bordered by Canada to the north and Mexico to the south. The state of Alaska is in the northwest of the continent, with Canada to the east and Russia to the west, across the Bering Strait. The state of Hawaii is an archipelago in the mid-Pacific. The country also possesses several territories in the Pacific and Caribbean.

At 3.79 million square miles (9.83 million km²) and with over 312 million people, the United States is the third or fourth largest country by total area, and the third largest by both land area and population. It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many countries. The U.S. economy is the world's largest national economy, with an estimated 2011 GDP of $15.1 trillion (22% of nominal global GDP and over 19% of global GDP at purchasing-power parity). Per capita income is the world's sixth-highest.

George Washington (February 22, 1732 [O.S. February 11, 1731] – December 14, 1799) was the first President of the United States of America, serving from 1789 to 1797, and the dominant military and political leader of the United States from 1775 to 1799. He led the American victory over Great Britain in the American Revolutionary War as commander-in-chief of the Continental Army from 1775 to 1783, and presided over the writing of the Constitution in 1787. Washington became the first president, by unanimous choice, and oversaw the creation of a strong, well-financed national government that maintained neutrality in the wars raging in Europe, suppressed rebellion, and won acceptance among Americans of all types. His leadership style established many forms and rituals of government that have been used since, such as using a cabinet system and delivering an inaugural address. Washington is universally regarded as the "Father of his country."

Barack Hussein Obama II (ⁱ/bəˈrɑːk huːˈseɪn oʊˈbɑːmə/; born August 4, 1961) is the 44th and current President of the United States. He is the first African American to hold the office. In January 2005, Obama was sworn in as a U.S. Senator in the state of Illinois. He would hold this office until November 2008, when he resigned following his victory in the 2008 presidential election.

Born in Honolulu, Hawaii, Obama is a graduate of Columbia University and Harvard Law School, where he was the president of the Harvard Law Review. He was a community organizer in Chicago before earning his law degree. He worked as a civil rights attorney in Chicago and taught constitutional law at the University of Chicago Law School from 1992 to 2004. He served three terms representing the 13th District in the Illinois Senate from 1997 to 2004.

Following an unsuccessful bid against the Democratic incumbent for a seat in the United States House of Representatives in 2000, Obama ran for the United States Senate in 2004. Several events brought him to national attention during the campaign, including his victory in the March 2004 Illinois Democratic primary for the Senate election and his keynote address at the Democratic National Convention in July 2004. He won election to the U.S. Senate in Illinois in November 2004. His presidential campaign began in February 2007, and after a close campaign in the 2008 Democratic Party presidential primaries against Hillary Rodham Clinton, he won his party's nomination. In the 2008 presidential election, he defeated Republican nominee John McCain, and was inaugurated as president on January 20, 2009. Nine months later, Obama was named the 2009 Nobel Peace Prize laureate. In April 2011, he announced that he would be running for re-election in 2012.