Supporters listen as Illinois Senator and Democratic presidential candidate Barack Obama addresses a campaign rally at Washington Square Park in New York, 27 September 2007. Obama, who trails New York Senator Hillary Clinton in the polls, addressed some 20,000 supporters in a park located at the gates of New York University (NYU) in an effort to boost his support to win the Democratic party's nomination for the 2008 presidential elections. Getty Images logo Getty Images 53 months ago

Supporters listen as Illinois Senator and Democratic presidential candidate Barack Obama addresses a campaign rally at Washington Square Park in New York, 27 September 2007. Obama, who trails New York Senator Hillary Clinton in the polls, addressed some 20,000 supporters in a park located at the gates of New York University (NYU) in an effort to boost his support to win the Democratic party's nomination for the 2008 presidential elections.