Earlier today I noted that Rasmussen Reports found that Hillary Clinton's long-standing large lead over Barack Obama in national polling had all but vanished, falling within the poll's margin of error. Now a new national poll from Gallup shows that Clinton's lead hasn't essentially evaporated -- it has actually evaporated.

Sen. Hillary Rodham Clinton and Sen. Barack Obama each drew 33% of the support from Democrats surveyed in its latest national poll, Gallup just announced.

In mid-December, well before Obama won last Thursday's Democratic caucuses in Iowa, Clinton held an 18-percentage point lead over him in Gallup's survey -- 45% to 27%.

Before today, Obama had never held or even shared the national lead with Clinton in Gallup's polling.

John Edwards remains third in Gallup's polling of Democrats. His support: 20%, vs. 15% in mid-December.

It's not clear how durable these numbers will be -- or if they even represent the end of the trend or just the beginning. At present, with a tie nationally, it's not clear that Clinton would be able to make up for early losses in the February 5 states, and she certainly could not if this trend continues and Obama actually takes a significant national lead. Nevertheless, this growth in support for Obama nationally could prove fleeting. There is quite a bit of time, still, between now and the beginning of February (nearly a month, in fact...), so there could be a potential for Clinton to stop some of the hemorrhaging of her support in time to make a real push for the big states that will chose their delegates on the superest of super Tuesdays.

Yet even leaving aside the longer term meaning of these numbers, one cannot help but think that this poll could serve to reinforce the results of Iowa in further indicating to voters nationwide, through the establishment media, that Obama can win. This is big time news for the Obama campaign in the short term, a further momentum boost at a time when it is trying to make its final push to make another statement tomorrow night. We've got a heckuva campaign on our hands, folks.

And one more point... John Edwards is not going away. He has vowed to stay in the race through the convention, for whatever that's worth, and he continues to maintain substantial support nationwide. It's not clear to me if he has a path to the nomination at this point -- I had trouble seeing one for him even in the case that he had won Iowa -- but it does seem quite possible that he will continue to play a meaningful role in this race for some time to come.