Barack Hussein Obama was sworn in as the 44th president of the United States on Jan. 20, 2009. The son of a black man from Kenya and a white woman from Kansas, he is the first African-American to ascend to the highest office in the land.

He defeated Hillary Rodham Clinton in a lengthy and 苦 primary battle before defeating Senator John McCain, the Arizona Republican, in November 2008.

As president, Mr. Obama has won passage of a number of sweeping pieces of legislation, notably a health care bill that will eventually provide near-universal coverage, a goal that had eluded Democratic presidents...