In any political race, this is true. Elections are about competing visions to solve the problem in your community, your state or your country. And there's no better format than a debate to lay those differences out for all to see. But it's even more true in this 2020 Democratic presidential race , where -- if the reverberations from the first debate last month are any indication -- the debates will play an outsized role in how the contest plays out.

Consider where we were before the first debate(s). (There were two, on consecutive nights due to the massive number of candidates, 20, who qualified.) Former Vice President Joe Biden was a clear and strong frontrunner. Vermont Sen. Bernie Sanders had settled into second -- albeit with Massachusetts Sen. Elizabeth Warren nipping at his heels a bit. California Sen. Kamala Harris had sagged back a bit -- seemingly in search of some momentum following the extremely strong start to her campaign.

Then came the debates. Harris was the breakout star , with Warren putting in a very solid performance as well. Biden and Sanders underwhelmed. And suddenly we had a different race. Harris shot up in both national and key early state polls. Biden dipped, as did Sanders. The momentum Warren had been building pre-debate kept up.

That's a LOT of movement based off of two debates held on back-to-back nights in late June.

So why did the debate(s) have such an impact? The biggest reason is that, unlike, say, the 2016 Democratic race, this one features a massive field without a clearly dominant frontrunner. There's a lot of candidates in the race that voters still don't know all that much about -- and because the field is so big, it's hard to learn about them short of a concentrated moment like a debate.

When someone like Harris pops , then, people who didn't know all that much about her but like what she said either jump from the undecided camp to hers -- or leave a candidate they are more loosely aligned with to get on her bandwagon. It remains to be seen whether, in the coming CNN debates Tuesday and Wednesday in Detroit, a voter who jumped from Biden to Warren after the first debate might jump back to Biden if he performs better. My guess is they might.

The broader point here is simple: Tuesday and Wednesday are going to be a very big deal for all 20 of the candidates on the stage. And with the Democratic National Committee raising the standards of qualification to make it into the third debates in September, this might be the last, best chance many of these candidates have to boost their support before it's curtains for their campaigns.

Below, the 10 candidates with the best chance at winning the Democratic nomination.

10. Andrew Yang: Yang's performance in the first debate was sort of meh -- especially after all the online hype (and money) he's been able to generate in the campaign to date. Which led us to wonder whether he should be on the list at all? But Yang's donor reach likely means he will meet the raised qualifications for the third debates in September -- and there just isn't anyone below him (11+) in our rankings that can say that with any certainty. (Previous ranking: 10)

9. Julián Castro: The former Housing and Urban Development secretary performed well in the last debate, and will now be on the same stage as Biden. That could be big if Castro wants to differentiate The former Housing and Urban Development secretary performed well in the last debate, and will now be on the same stage as Biden. That could be big if Castro wants to differentiate between their immigration policies (i.e. Biden's relative hawkishness on them). Castro already has the donors necessary to qualify for the September debates, but he's a little short on the polling qualifying front. A strong debate in Detroit could change that. (Previous ranking: 9)

8. Beto O'Rourke: There's not a lot to like here, which is why we are moving the former Texas congressman down one spot from where we had him in our last rankings. The O'Rourke people have been signaling that he is ready, willing and able to take the fight to South Bend, Indiana, Mayor Pete Buttigieg in next week's debate -- and maybe that will work? One piece of good news for O'Rourke: : There's not a lot to like here, which is why we are moving the former Texas congressman down one spot from where we had him in our last rankings. The O'Rourke people have been signaling that he is ready, willing and able to take the fight to South Bend, Indiana, Mayor Pete Buttigieg in next week's debate -- and maybe that will work? One piece of good news for O'Rourke: He's already qualified for the third debate . (Previous ranking: 7)

7. Amy Klobuchar: In a primary about electability, you'd think a senator who has won a In a primary about electability, you'd think a senator who has won a Midwestern swing state by at least 20 points three times would be in better position. In a dream world for Klobuchar, she uses her debate podium against Sanders and Warren to paint them as extreme -- and then sees Biden do poorly the following night. Klobuchar has the polling to qualify for the September debates, but lacks the donors. A strong debate in Detroit can help her on the latter. (Previous ranking: 8)

6. Cory Booker: The next week feels like a very big one for the New Jersey senator. Unlike the : The next week feels like a very big one for the New Jersey senator. Unlike the first debates last month, Booker will share a stage with Biden , and he's already signaling that he isn't afraid of going after the former vice president hard on issues of race. Booker benefited from his first clash with Biden (over the former veep's seeming praise for a segregationist senator) and he's spent this week taking shots at Biden's criminal justice reform plan. Expect lots more of that Wednesday night in Detroit. (Previous ranking: 6)

5. Pete Buttigieg: If primaries were about money, the South Bend mayor would be in the driver's seat. Instead, Buttigieg probably needs two things to happen in Detroit to regain some of his lost momentum from the beginning of the year. He could stand to benefit from Harris or Warren having poor performances. (Both, like Buttigieg, do well with If primaries were about money, the South Bend mayor would be in the driver's seat. Instead, Buttigieg probably needs two things to happen in Detroit to regain some of his lost momentum from the beginning of the year. He could stand to benefit from Harris or Warren having poor performances. (Both, like Buttigieg, do well with well-educated white voters .) Additionally, Buttigieg needs to do something, anything, to connect with black voters . (Previous ranking: 5)

4. Bernie Sanders: For Sanders, who has clearly lost some ground to Warren among liberals, the debate draw worked out very well. He and the Massachusetts senator will be center stage on Tuesday night surrounded, largely, by lesser-known and more moderate candidates. That affords Sanders an opportunity to contrast his record with Warren's in hopes of winning back some of those lost liberals. But Sanders has never really been one to follow political conventional wisdom and it's not at all clear to us that he has any plans to go after Warren. (Previous ranking: 4)

3. Elizabeth Warren: One of the big questions heading into Detroit is whether the senior senator from Massachusetts will try to take down Sanders. They share the debate stage and many of the same policies. As Warren has moved up in the polls, she's supplanted Sanders as the leader among self-described One of the big questions heading into Detroit is whether the senior senator from Massachusetts will try to take down Sanders. They share the debate stage and many of the same policies. As Warren has moved up in the polls, she's supplanted Sanders as the leader among self-described very liberal voters . Still, Sanders and Warren supporters differ in many ways (including educational attainment). Warren may decide the best play is to play nice to keep her momentum going. (Previous ranking: 3)

2. Kamala Harris: Harris is sitting pretty after her star turn in the last debate. And she's probably got the matchup she wanted -- standing next to Biden on the second night. Because she owned him on busing in the first debate, the rematch storyline will be the dominant one heading into Detroit. Biden will be more ready for attacks from Harris but, in truth, she may not necessarily need to make them. She has considerable momentum in the race already -- and may not want to risk it by going after Biden again. (Previous ranking: 2)

1. Joe Biden: The only piece of advice the former vice president needs for the second debate is "don't have a repeat of the first debate." Biden The only piece of advice the former vice president needs for the second debate is "don't have a repeat of the first debate." Biden still holds the lead in the primary -- and has seen his polling come back somewhat after a dip following his poor first debate performance.