The second Democratic presidential debate will take place in just over a week, this time in Detroit. After what transpired in Miami, almost every candidate has something to prove.

CNN, which will host the two nights of debate, found a smart system to assure relative balance between upper- and lower-tier candidates. That will create opportunities and dynamics on both nights that will differ in important ways from the first debate in Miami.

Among the candidates in the upper tier of the polls, Sen. Elizabeth Warren (Mass.) and Sen. Bernie Sanders (I-Vt.) will join eight other candidates on July 30, while former vice president Joe Biden and Sen. Kamala D. Harris (Calif.) will join the eight remaining qualifiers on July 31.

For Harris and Biden, who clashed in Miami, this represents a rematch. Warren and Sanders, the two leading liberals in the contest for the Democratic nomination, share many ideas, but this will mark the first time they have shared a debate stage.

Much of the attention is focused on what these two pairings will produce, substantively, stylistically and politically. Yet the other 16 candidates won’t be potted plants, no matter how much the CNN moderators seek to pit the leaders against one another. For many of those 16, the stakes are especially high, in part because some of them might not meet the rules for qualifying for the September debate in Houston.

Biden needs to bounce back after Miami. Not only was he hit hard by Harris over his opposition to mandatory school busing in the 1970s and his comments about working with segregationist senators decades ago, his overall performance lacked spark, crispness and energy, all encapsulated by an unfortunate comment: “My time is up. I’m sorry.”

Democratic presidential candidates former vice president Joe Biden, left, Sen. Bernie Sanders (I-Vt.) and Sen. Kamala D. Harris (Calif.) speak simultaneously during the primary debate on June 27 in Miami. (Wilfredo Lee/AP)

Biden can expect more criticism in Detroit. It could come from Harris, but it could just as easily come from Sen. Cory Booker (N.J.), who told The Washington Post’s Robert Costa during an interview before a live audience on Thursday that the 1994 crime bill that Biden helped steer to passage was one of the worst pieces of legislation ever. An exchange over that issue appears inevitable.

Harris might be happy to let Booker take the lead against Biden, assuming that Booker does not challenge her. She had her moment in Miami, a well-planned and well-executed attack that accomplished, at least in the short term, what she had wanted. But she also has drawn more scrutiny on her positions on other issues. Taking on Biden again might not serve her best interests.

Still, Harris must be prepared. If the former vice president comes after her, on health care or the busing controversy, there will be an unavoidable second round between the two. Given that she’s trying to argue she is equipped to prosecute the case against President Trump in 2020, Harris will have to demonstrate that she can counter effectively when attacked. A perpetuation of the Biden-Harris dynamic of Miami carries as many risks as rewards.

If Biden is set up for a rebound, much still depends on his ability to deliver. He continues to offer uneven performances on the campaign trail. As the person atop the state and national polls, as someone who has run for president twice previously, as the man who ran two general elections as Barack Obama’s running mate, and as the candidate who claims to have the best chance of defeating Trump in 2020 — Biden is dealing with high expectations. Still, it should not be difficult to have a better night the second time around.

Warren made the most of not having to share the stage in Miami with Biden, Sanders or Harris. Her discipline and her skill at delivering her own message were on display. She took advantage when she was in the spotlight and seemed content to stay out of other scrums.

Sen. Elizabeth Warren (Mass.) speaks during the first night of the Democratic primary debate on June 26 in Miami. (Wilfredo Lee/AP)

She and Sanders are friends of many years and have similar perspectives, if sometimes different solutions, about what they see as an economic and political system rigged against the middle class. It’s likely they will be encouraged by one of the CNN moderators to point out their differences. Warren might decide to avoid engaging or deflect questions back to issues she wants to highlight. But will Sanders, who has lost some ground, be content to do the same?

First-night friction almost certainly will come from others on the stage. Several of them have moderate views they will want to contrast with Warren and Sanders. One is former Colorado governor John Hickenlooper, who has been outspoken about the leftward movement of the party and who knows he needs a spark for his candidacy. Former Maryland congressman John Delaney is another, given what he did in Miami. Sen. Amy Klobuchar (Minn.) has cast herself as a results-oriented politician who thinks the liberals are offering some unrealistic proposals. But she has been gentle in making that point.

Two others who will debate on the first night could have agendas other than getting into a scrap with Warren and Sanders, or the others.

South Bend, Ind., Mayor Pete Buttigieg is running close to the leading four in polls in Iowa and New Hampshire, but nationally is further back. He has shown a desire to push forward his own ideas, to highlight his profile (younger generation, military veteran), and not to pick fights.

Former Texas congressman Beto O’Rourke had a poor night in Miami, consistent with a disappointing run since he announced his candidacy. He is passionate on the campaign trail and continues to display skills as a retail candidate. But he has been on a downward trajectory. He lacked focus in the first debate and will feel the pressure to step up in Detroit. Does it serve him to try to make a moment by attacking a rival or simply to deliver a tighter and sharper message?

The same can be said for Gov. Steve Bullock (Mont.). He did not qualify for the Miami debate, so this will be his moment of introduction to most viewers. He hopes to impress Democratic voters by highlighting that he won reelection in 2016 in a red state and produced some progressive results. He’s not yet tied those points to a larger national message about the direction of the Democratic Party.

Rep. Tim Ryan (Ohio), an advocate for economic policies aimed at working-class voters will also debate on the first night, as will author Marianne Williamson.

The second night will include every candidate of color in the race. It also will feature several candidates struggling to get attention, including Sens. Michael F. Bennet (Colo.) and Kirsten Gillibrand (N.Y.) and Gov. Jay Inslee (Wash.).

Bennet, a moderate, took on Biden in Miami. Will he do that again or focus more on his concerns that the Democrats are in danger of being defined out of the mainstream? Gillibrand repeatedly and energetically sought to inject herself into the first debate, but with limited success. Inslee is the climate change candidate but didn’t make much of a mark in Miami.

New York Mayor Bill de Blasio stood out in Miami through his interruptions and by asserting his liberal credentials. But it hasn’t helped him much with Democratic voters.

Julián Castro, former secretary of housing and urban development, benefited from his exchange in Miami with O’Rourke over immigration. The Miami debate helped raise his profile and some badly needed funding. Will he look at Biden and Harris as fresh opportunities for contrast?

In the first debate, Castro pushed the other candidates to embrace his plan to decriminalize the border. He’ll be asked to defend that idea and rebut the charge that it leaves Democrats open to the label of the “open borders” party.

The second night also will include Rep. Tulsi Gabbard (Hawaii) and entrepreneur Andrew Yang.

Democratic voters are looking for the person they believe can defeat Trump and are measuring the candidates through that lens. That means it’s not necessarily in the candidates’ interest at this point to get into fights with each other. They do need to present an appealing rationale for why they are seeking the presidency, to show a combination of character and message that sets them apart from their rivals.

However, CNN has sponsored many debates and the network’s style is to prod and provoke the participants to clash with one another. That suggests Detroit could be even noisier and more contentious than Miami.