ST. PAUL, MN - JUNE 3:  Democratic presidential candidate Sen. Barack Obama (D-IL) (R) and his wife Michelle Obama bump fists at an election night rally at the Xcel Energy Center June 3, 2008 in St. Paul, Minnesota. Obama clinched the Democratic presidential nomination following today's primaries in South Dakota and Montana, although his rival Sen. Hillary Clinton (D-NY) has not yet conceded the race.  (Photo by Scott Olson/Getty Images)