(This is the 22nd edition of our power rankings of Democrats most likely to get their party's presidential nomination in 2020.)
(CNN) Within the first 10 minutes of Tuesday's fourth presidential debate, you could tell something fundamental had changed in the race: Elizabeth Warren is the new front-runner.
The Massachusetts senator was attacked from all sides from the get-go -- on how she planned to fund her "Medicare for All" plan, on the "punitive" nature of her policy solutions, and on her supposed claims to be the only one in the field who had bold ideas.
By our count, at least seven other candidates on the stage attacked Warren at some point during the three-hour debate. That dynamic ensured that the fourth debate wouldn't be as successful for Warren as the previous three -- no one can take that amount of incoming and emerge unscathed -- but also proved, very clearly, that no matter what the polls show, her rivals believe her to be the one to beat in this race.
We've reflected that changed reality in our latest 2020 rankings. Below, the 10 men and women with the best chance of emerging as the Democratic nominee in 2020.
10. Tom Steyer: If you saw an unfamiliar man on Tuesday's debate stage, you probably were looking at Steyer. The businessman managed to qualify for the debate by buying a lot of ads in the early primary states to boost his poll numbers. It won't be the last time Steyer appears on stage, as he has already qualified for November's debate. That puts him in a better position than a majority of Democrats running. (Previous ranking: 10)
9. Beto O'Rourke: It's not at all clear to us that the former Texas congressman understands his current peril in this race. He hasn't qualified for the November debate and, if his performance in Tuesday night's gathering is any indication, he probably won't. Try to remember a memorable moment for O'Rourke from the debate. Chances are that if you can come up with one, it's when South Bend, Indiana, Mayor Pete Buttigieg smacked him down for an alleged lecture on courage. Not great, Bob! (Previous ranking: 6)
8. Andrew Yang: Although Yang has been on the stage for every debate so far, Tuesday seemed like the first one where he actually got some real attention. Once the number of debaters shrinks, the question is, does Yang get even more attention? He's going to need it. Yang has a devoted set of supporters, but his unconventional message has failed to light up most Democrats. (Previous ranking: 8)
7. Amy Klobuchar: The Minnesota senator has been our longtime dark horse in this race, and her performance on Tuesday -- finally -- showed what she's capable of. Klobuchar was pointed -- especially with Warren -- and got to make her case that she is a Midwesterner who has a track record of winning where Democrats need to win to beat President Donald Trump. Will it matter? Well, Klobuchar raised more than $1 million in the 24 hours after her strong debate showing but she still hasn't qualified for the November debate. So, maybe? (Previous ranking: 9)
6. Cory Booker: If you watched Tuesday night's debate, you saw another solid (even if not spectacular) performance from Booker. He'll need another one next month, too. Right now, the Democratic race is mostly a fight between Biden and Warren. What Booker wants is to be an alternative, if voters start looking for one. Unlike anyone in our top five, Booker hasn't had his moment in the sun. He remains popular in Iowa, so he just may get that moment. (Previous ranking: 7)
5. Kamala Harris: The only reason the California senator stays in the top 5 after what was a hugely lackluster debate performance is that she had $10 million on hand at the end of September and polling still puts her above the 2% and less crowd -- albeit narrowly. The debate was a microcosm of Harris' problems in this race. Does she really think that goading Warren to support her call for a Twitter ban on Trump is going to get her where she wants to go? (Previous ranking: 5)
4. Pete Buttigieg: Initial data suggests that the South Bend mayor benefited by going after Warren in Tuesday's debate. Let's be very real: Buttigieg's bid relies almost entirely on Iowa. He has to finish strong and probably needs to win the caucuses. He's within 10 points of the lead there and is very well liked. But even if Buttigieg wins in Iowa, he needs to show some signs of life with nonwhite voters. So far, his support with them is close to 0%. (Previous ranking: 4)
3. Bernie Sanders: If you were worried that Sanders' recent heart attack would fundamentally change him or his presidential bid, Tuesday's debate made clear that wasn't happening. Sanders was as acerbic and blunt as ever. And the news that he has secured the endorsement of Rep. Alexandria Ocasio-Cortez (as well as several other members of the Squad) changed the story from one about his health to one focused on his continued support from high-profile liberals. That, plus Sanders' $33 million-plus war chest, means he is going to be in the race for, well, about as long as he wants to be. (Previous ranking: 3)
2. Joe Biden: The former vice president finds himself not in the top spot our list for the first time since April. That's what happens when you're spending campaign money faster than you can raise it. The good news for Biden is that he still leads in the average national primary poll, and his support among black voters remains as solid as ever. Still, if there is any doubt that Biden's front-runner status isn't as clear as it once was could be seen by the lack of attacks from fellow Democrats in Tuesday's debate. (Previous ranking: 1)
1. Elizabeth Warren: The Massachusetts senator knocks Biden out of the top spot this week after holding down the number two position since early August. Why? She's the clear Iowa front-runner. She's got a geographic appeal in New Hampshire. Liberals love her. She's positioned herself as the "ideas" candidate. She has $25 million to spend in the race. She has all the momentum right now. What could stop Warren? You saw a preview of it in Tuesday's debate: Her support of Medicare for All coupled with her clear unwillingness to acknowledge the obvious -- that funding the program will require raising taxes on middle-class families. (Previous ranking: 2)