Inexperienced Sentator Barack Obama has risen from virtually nowhere to the threshold of the White House. Panorama visits his political home in Chicago's South Side as well as the crucial battleground state of Ohio to find out how he has achieved this. But as the new - and just as unlikely - vice-presidential challenger Sarah Palin slows him in his tracks, could the current financial crisis engulfing the Republican party put Obama on the home straight? Matt Frei investigates.