The first features the top tier: Sens. Bernie Sanders (Vermont) and Elizabeth Warren (Massachusetts) as well as former Vice President Joe Biden and South Bend, Indiana Mayor Pete Buttigieg. That race is relatively stable, with the four candidates -- generally -- being the only four in double-digits in early states and in national polling.

The second race is among the bottom six (and beyond) -- a group that now includes former Massachusetts Gov. Deval Patrick, who announced his candidacy Thursday morning and, likely, former New York City Mayor Michael Bloomberg.

These are candidates desperately trying to break into that top four -- whether through a surprisingly strong debate performance or some other sort of moment on the campaign trail. There's a LOT more movement -- both up and down -- among this group as they are forced into riskier strategies (going all in on a single state, launching early ads) in order to try to make a move in Iowa or New Hampshire. Those gambles often don't pay off, leading candidates to drop down our list or leave the race entirely.

Below, our new top 10 -- ranked by the likelihood of the candidate winding up as the party's nominee.

10. Tom Steyer: The good news for the first billionaire on our list is that he is in next week's debate. The bad news is that he The good news for the first billionaire on our list is that he is in next week's debate. The bad news is that he hasn't qualified for next month's because he hasn't reached the necessary support in the polls. His inability to do so comes despite spending millions of dollars on advertising. It's tough to see how Steyer can win, given that he hasn't yet been able to move the needle, even with millions spent. (Previous ranking: 9)

8. Cory Booker: The New Jersey senator keeps waiting and waiting (and waiting) for a moment -- ANY moment -- in this race. He still hasn't had one, and it's starting to get late. Booker is in the debate next week and, honestly, that may be his best chance. Booker has already struggled once with raising enough money to keep the lights on and if he can't find a moment soon, it's hard to see how he can raise enough money to keep going. (Previous ranking: 6)

7. Andrew Yang: The tech entrepreneur just keeps on overperforming expectations. He's going to make the debate stage next week -- and is nearly certain to make it in December as well. Plus, Yang raised : The tech entrepreneur just keeps on overperforming expectations. He's going to make the debate stage next week -- and is nearly certain to make it in December as well. Plus, Yang raised $10 million in July, August and September , a sum that allows him to build out his campaign in early states and begin communicating beyond his (very) ardent backers. Yang is beginning to do just that -- beginning ad campaigns in Iowa and New Hampshire . Can Yang keep growing? If past if prologue, don't bet against it. (Previous ranking: 8)

6. Kamala Harris: Unlike every candidate below her, Harris has qualified for December's debate. On polling support alone, she belongs at No. 6. Harris also remains a clear second : Unlike every candidate below her, Harris has qualified for December's debate. On polling support alone, she belongs at No. 6. Harris also remains a clear second in the endorsement primary , even if those endorsements haven't been rolling in lately. Unfortunately for Harris, the returns on her all-in-on-Iowa campaign have been less than good. She got only 3% in Monmouth recent poll. Oy. (Previous ranking: 5)

5. Amy Klobuchar: The Minnesota senator has already qualified for not just next week's debate but also the December one. Which is a big deal, because she has been solid-to-good in the past few debates -- casting herself as a pragmatic (and electorally successful) alternative to both the liberal and establishment wings of the party. Her Midwestern ties also give her a foothold in Iowa -- where she likely needs to finish in the top three. (Previous ranking: 7)

4. Bernie Sanders: Sanders' path to the nomination is clear: win in Iowa, win in New Hampshire and start a momentum train. Polling in : Sanders' path to the nomination is clear: win in Iowa, win in New Hampshire and start a momentum train. Polling in Iowa has him close to the top as does the polling in New Hampshire . You can't say he leads in either state, though. And even if he pulls those two states off, he still has to show more of an ability to win minority voters. Additionally, it's not entirely clear whether he can overcome what is likely to be real resistance from the establishment. Sanders is also six weeks out from suffering a heart attack on the campaign trail, but is going to be in this race -- no matter what -- for a very long time given that he ended September with more than $33 million in the bank. The forever question for Sanders is whether he can grow in any significant way beyond the hardcore supporters who will be with him no matter what. (Previous ranking: 4)

3. Pete Buttigieg: Buttigieg is in the midst of a second major moment in the 2020 race. (The first was in the spring when he surged from nowhere to relevance.) Recent polls in both : Buttigieg is in the midst of a second major moment in the 2020 race. (The first was in the spring when he surged from nowhere to relevance.) Recent polls in both Iowa and New Hampshire show Buttigieg at or near the top of the field -- a remarkable accomplishment given where Buttigieg started. (As I noted, he started nowhere.) Buttigieg has to show he can maintain his momentum over the next 80-ish days (Previous ranking: 3)

1. Joe Biden (tie): You could argue that Biden is the only candidate who, by winning Iowa, would almost certainly win the nomination. That's because Biden has a clear lead in the endorsement primary and a strong foundation of support with black voters. The problem is that Biden's not clearly ahead either Iowa and New Hampshire and could easily lose both. His campaign has had trouble raising money, which may leave him struggling in an extended primary fight. (Previous ranking: 2)