Democratic presidential candidate Senator Barack Obama shakes hands as he campaigns outside a Metro subway stop on the District of Columbia's primary election day on Pennsylvania Avenue in Southeast Washington, February 12, 2008. (Jim Bourg/Reuters)
Democratic presidential candidate Senator Barack Obama carries a box of donuts and a container of hot coffee that he purchased for supporters and commuters, as he walks out of a donut shop with Washington Mayor Adrian Fenty (R) to campaign outside a Metro subway stop, on the District of Columbia's primary election day in Southeast Washington February 12, 2008. (Jim Bourg/Reuters)
Democratic presidential candidate Senator Barack Obama (D-IL) shakes hands with an employee working behind the counter in a donut shop as he purchased donuts for supporters while campaigning in Southeast Washington on the District of Columbia's primary election day February 12, 2008. (Jim Bourg/Reuters)
Democratic presidential candidate Senator Barack Obama gives a box of donuts and a container of hot coffee that he purchased to his as he campaigns outside a Metro subway stop, on the District of Columbia's primary election day in Southeast Washington, February 12, 2008. (Jim Bourg/Reuters)
A supporter of Democratic presidential candidate Sen. Barack Obama (D-IL) greets voters as they arrive at a polling station near the US Capitol in primary elections in Washington February 12, 2008.
(Jonathan Ernst/Reuters)
Democratic presidential hopeful, Sen. Barack Obama, D-Ill., greets commuters during a get out the vote at the Eastern Market Metro Station in Washington, Tuesday, Feb. 12, 2008. (AP Photo/Rick Bowmer)