Beginning now, we're going to rank both the Democrats and Republicans each week. Look for new GOP rankings in a few days.

These rankings are ordered by likelihood of winning the Democratic Party primary and are based on a number of factors, including organization, money, buzz and polling. Click here for the old Republican rankings.

1. Hillary Clinton -- The margin between Clinton and Obama is as narrow as it's ever been. She's ahead because there's a plausible scenario for her to win the nomination even if she loses Iowa and New Hampshire; that scenario does not exist for Obama. Still, the tide is moving in the wrong direction for her.

2. Barack Obama -- He's on a roll, but is it too soon? Momentum's a powerful thing, but one has to have it at the right time; Edwards got it a few days too late in '04, or he would have been the nominee. Obama's big test may actually be after New Hampshire, when he could start to get REAL front-runner treatment from the media. For now, he is still getting gee-whiz coverage, to the chagrin of the Clinton camp.

3. John Edwards -- The biggest hurdle in Edwards' way? It's Clinton, not Obama. Edwards and Clinton share more supporters than Edwards and Obama. Edwards is hoping for the blue-collar, older Dem support. That's the heart and soul of Clinton's support.

Continue reading our Democratic race rankings.

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