Preview of the Democratic Convention

Next week's Democratic convention is going to be an historic event as the party nominates the first African American presidential candidate in US history. In a major departure from tradition, Barack Obama will deliver his acceptance speech before a crowd of 75 thousand at the football stadium in Denver and a worldwide audience of millions. This will happen 45 years to the day after Dr. Martin Luther King, Jr. delivered his "I Have a Dream Speech" in Washington. But the polls are showing a close race between McCain and Obama and the campaigns seem mired in mud, with candidates trading accusations about who is more "elitist." What can we expect from the convention? Will the vice-presidential choice boost Obama's chances? Will Hillary's supporters get on board? Can those polls really be trusted?