U.S. President Barack Obama before addressing U.S. Conference of Mayors at White House in Washington

 
U.S. President Barack Obama before addressing U.S. Conference of Mayors at White House in Washington
U.S. President Barack Obama (L) takes a moment to think before Vice President Joseph Biden (R) introduces him to speak to the U.S. Conference of Mayors in the East Room of the White House in Washington, February 20, 2009. REUTERS/Larry Downing (UNITED STATES)