Democratic Presidential candidate Barack Obama (R) and Vice Presidential candidate Joe Biden (L) appear on stage at the end of the Democratic National Convention 2008 at the Invesco Field in Denver, Colorado, on August 28, 2008. The Illinois senator tonight formally accepted his nomination as the first African-American from a major party to run for the White House before more than70,000 people. AFP PHOTO Paul J. RICHARDS (Photo credit should read PAUL J. RICHARDS/AFP/Getty Images)
WASHINGTON, DC - JANUARY 12: (AFP OUT) U.S. President Barack Obama (R) presents the Medal of Freedom to Vice-President Joe Biden during an event in the State Dining room of the White House, January 12, 2017 in Washington, DC. (Photo by Olivier Douliery-Pool/Getty Images)
WASHINGTON - JANUARY 30: President of the United States Barack Obama and Vice President Joe Biden talk during a college basketball game between Georgetown Hoyas and the Duke Blue Devils on January 30, 2010 at the Verizon Center in Washington DC. (Photo by Mitchell Layton/Getty Images)
CHARLOTTE, NC - SEPTEMBER 06: (L-R) Second lady Dr. Jill Biden hugs First lady Michelle Obama, as Democratic vice presidential candidate, U.S. Vice President Joe Biden greets Democratic presidential candidate, U.S. President Barack Obama on stage after accepting the nomination during the final day of the Democratic National Convention at Time Warner Cable Arena on September 6, 2012 in Charlotte, North Carolina. The DNC, which concludes today, nominated U.S. President Barack Obama as the Democratic presidential candidate. (Photo by Alex Wong/Getty Images)
DETROIT - SEPTEMBER 28: Democratic presidential nominee Sen. Barack Obama (L) (D-IL), hugs his vice-presidential running mate Sen. Joseph Biden (D-DE), at a rally September 28, 2008 in Detroit, Michigan. After participating in the first of three presidential debates Obama is campaigning in Michigan with a focus on his strategy for the recent national financial turmoil. (Photo by Bill Pugliano/Getty Images)
