According to the Gallup Daily Tracking Poll, Hillary Clinton held a 20-point national lead over Barack Obama as late as January 20.  A week ago, that lead was 15 points; three days ago, it was 9.  Today, in a national poll, Obama is within an astonishing 4 points of Clinton.  For the many of us wondering which way Edwards supporters would go, the poll seems to give an answer: they’re gravitating overwhelmingly towards Obama.  In the last four days, as John Edwards’s numbers have dropped by 6 points, Obama’s numbers have increased by exactly that number, while Hillary’s have dropped by a point.  If the trend of the last week holds, and barring any major developments (such as an Edwards endorsement, a Gore endorsement, or a significant gaffe by one of the candidates in tonight’s debate), Obama will be up over Clinton by 4 or 5 points on February 5th’s Super Tuesday primary.