The Presidency of Barack Obama began at noon EST on January 20,
2009 when he became the 44th President of the United States.
Obama was a United States Senator from Illinois at the time of
his victory over Arizona Senator John McCain in the 2008
presidential election. His policy decisions have addressed a
global financial crisis and have included changes in tax
policies, proposals to overhaul health care, foreign policy
initiatives and the phasing out of detention of prisoners at the
Guantanamo Bay detention camp in Cuba. He attended the G-20
London summit and later visited U.S. troops in Iraq. On the tour
of various European countries following the G-20 summit, he
announced in Prague that he intended to negotiate substantial
reduction in the world's nuclear arsenals, en-route to their
eventual extinction. In October 2009, Obama was awarded the
Nobel Peace Prize for "his extraordinary efforts to strengthen
international diplomacy and cooperation between peoples." The
presidential transition period began follow