In this Feb. 12, 2008, photo, presidential candidate Sen. Barack Obama greets supporters before a rally in Madison, Wis. President Obama is returning to the University of Wisconsin to ask young voters who helped propel him to the White House to support Democrats in key governor and U.S. Senate races. (Rick Bowmer / Associated Press)
Barack and Michelle Obama embrace on stage at the 2008 Democratic National Convention in Denver. (Shawn Thew / EPA)
Vice President Joe Biden and Afghan President Hamid Karzai join President Obama at a White House appearance in May 2009. (Ron Edmonds / Associated Press)
President Obama addresses a joint session of Congress in September 2011. (Kevin Lamarque / Associated Press)
President Obama speaks to supporters at a campaign fundraiser in Denver in May 2012. (Pablo Martinez Monsivais / Associated Press)
President Obama speaks during a May 2013 news conference in San Jose, Costa Rica. (Pablo Martinez Monsivais / Associated Press)
President Obama delivers an address in Tallinn, Estonia, on Sept. 3. (Mindaugas Kulbis / Associated Press)
President Obama speaks by phone at the White House with Jordan’s King Abdullah II in August 2014. (Jacquelyn Martin / Associated Press )
President Obama speaks to reporters at the White House in August 2014. (Alex Wong / Getty Images)
President Obama at a White House news conference in December. (J. Scott Applewhite / Associated Press)
President Obama, pictured on Christmas Eve in Hawaii, relieves stress on vacations and weekends by playing golf. (Nicholas Kamm / AFP/Getty Images)
