The problem with trying to assess a volatile Democratic race has never been illustrated better than the two polls this morning from the Washington Post/ABC News and the New York Times/CBS News. Yet even in the best-case scenario for Barack Obama, he still has his work cut out for him.

In the first poll, Obama has managed to shave Hillary Clinton's national lead from 30 percentage points to five in only a month. In the latter, Clinton's former 17-point national lead has dropped marginally to only 15 percentage points.

Until now, of course, national polls haven't mattered. But February 5th is a kind of national primary, so one can hazard a guess that the total vote that day will mirror the national numbers. Sure, there will be regional deviations and the candidates will target certain states and constituencies but the country and the states involved are just too large for any candidate to make more than a marginal difference in any.

For Obama to win, he first has to hope that the Post/ABC poll is more accurate than the Times/CBS one. Then, he needs to continue his upward momentum over the next three weeks, since even a five-point aggregate loss on Super Tuesday, while keeping him close, will probably put him behind in the delegate count to a front-runner who is likely to do better among the super-delegates than he does.

It's not an impossible task for Obama to go on and pass Clinton in the national numbers. But given the two hands to play in the coming weeks, he has the more difficult one.

To read Steven Stark's complete "Presidential Tote Board" blog, go to www.thephoenix.com/toteboard/