Democratic presidential hopeful Sen. Barack Obama, D-Ill., waves to tourists from Illinois as he is followed by the news media through the U.S. Capitol, Thursday, May 8, 2008 in Washington. Obama's unannounced visit to the Hill during House votes lasted more than half an hour. The Illinois senator told reporters that that he's not taking the Democratic presidential nomination for granted, and that he was asking members of Congress to support his White House candidacy. (AP Photo/Susan Walsh)
