The Democratic National Committee has announced which 20 candidates qualified for this month’s second Democratic presidential debate — but the important question about how they’ll be split among the two-night event remains to be settled.

There was little drama with the roster itself, which was almost exactly the same as last month’s lineup of 20 candidates — the only difference is that California Rep. Eric Swalwell, who quit the race, was replaced by Montana Gov. Steve Bullock.

On Thursday, in the 8 pm Eastern hour, CNN will air a live drawing to determine which candidates will debate on the first night and which will debate on the second.

The question of which candidates are actually onstage with each other proved enormously important last time around — as Sen. Kamala Harris’s confrontation with Joe Biden turned out to be the breakout moment and boosted her campaign in the polls afterward.

CNN has designed the drawing in a way that will ensure the top-tier candidates in polls — Biden, Harris, Sen. Elizabeth Warren, and Sen. Bernie Sanders — will be split, with two on each night.

The debate itself will take place on Tuesday, July 30 and Wednesday, July 31, in Detroit, at 8 pm Eastern on each night.

And while it will be another crowded, lengthy affair, it’s also likely to be the last such event, since there are much tougher qualification rules in place for the third debate in September. That means, for perhaps most of the candidates onstage, it’s now or never.

Who qualified?

Expecting an extraordinary large field of candidates, the DNC announced months ago how it would determine who qualifies for the first two Democratic debates. It set lenient standards, to help let even lower-profile, little-known candidates have a fair shot to get in the debate.

But they also had to draw the line somewhere. So the second debate, like the first, will be capped at 20 candidates. Since there are 25 at least somewhat notable Democrats in the race, that means, like last time around, the real question was who wouldn’t qualify.

The qualification rules, too, were the same as last time around. A candidate could qualify by polling — hitting 1 percent in three separate polls released on or before July 16. (These can be national or early-state polls from approved polling organizations.) A candidate could also qualify by raising money from at least 65,000 unique donors (with at least 200 donors each in 20 states).

If more than 20 candidates met either the polling or the donor threshold, candidates who met the polling threshold were advantaged. After that, a tiebreaker was to kick in (but one didn’t end up being necessary).

All 19 candidates still in the race who made the cut last time qualified again. That’s Joe Biden, Elizabeth Warren, Kamala Harris, Bernie Sanders, Pete Buttigieg, Beto O’Rourke, Cory Booker, Amy Klobuchar, Julián Castro, Kirsten Gillibrand, Jay Inslee, Tulsi Gabbard, Michael Bennet, John Hickenlooper, Bill de Blasio, Tim Ryan, John Delaney, Andrew Yang, and Marianne Williamson.

The one exception is Rep. Eric Swalwell of California, who quit the race last week and whose spot therefore went up for grabs. Gov. Steve Bullock of Montana ended up getting it.

Rep. Seth Moulton of Massachusetts; Miramar, Florida, Mayor Wayne Messam; and former Alaska Sen. Mike Gravel, who all failed to qualify last time, also failed to do so this time around. Two more recent entrants into the race — former Rep. Joe Sestak of Pennsylvania and billionaire Tom Steyer — also failed to qualify.

All in all, it’s the same 20 candidates as the last debate, except with Swalwell replaced by Bullock.

The more interesting question is which candidates will debate on which night

Because putting 20 candidates onstage together would be absurd, this second debate, like the first, will be a two-night event, with each night featuring 10 candidates. CNN has said the lineup for each night will be determined by a drawing, to be conducted this Thursday.

Now, when NBC News did a similar drawing for the first debate, it separated the candidates into two groups — those who polled at 2 percent or above, and those who did not. It drew randomly from within each group but ensured the groups as a whole would be split evenly among the two nights.

This seemed to be an effort to prevent all the top-polling candidates from being randomly placed on the same night (which would create a dynamic where there was one clearly top-tier debate and one “kids’ table” debate).

This only sort of worked. By luck of the draw, four of the top five candidates overall — Biden, Sanders, Harris, and Buttigieg — ended up together on the same night, with Warren excluded. (Warren was sorted with a few candidates polling just barely above 2 percent by NBC’s standards — Booker, O’Rourke, and Klobuchar.) If ratings are any indication, this wasn’t a huge problem, though.

Now it’s CNN’s turn. Their methodology is similar to NBC’s, but they’ve tweaked it so there will be drawings from three separate groups of candidates.

The top tier (2 on each night) : Biden, Harris, Sanders, and Warren

: Biden, Harris, Sanders, and Warren The middle tier (3 on each night) : Buttigieg, Booker, Klobuchar, O’Rourke, Castro, and Yang

: Buttigieg, Booker, Klobuchar, O’Rourke, Castro, and Yang The bottom tier (5 on each night): Bennet, Bullock, de Blasio, Delaney, Gabbard, Gillibrand, Hickenlooper, Inslee, Ryan, and Williamson

While this may all seem rather technical, it’s clear from last time around that this could matter a great deal. Last time, Warren, who had been on the rise before the debate, was assigned a night with no other top-tier candidates. This meant she had no opportunity to challenge Biden or Sanders face to face, but it also let her be the star of the first night (an opportunity that, say, Buttigieg might have liked to have had).

Even more importantly, if Harris and Biden had not been assigned to the same night, she would not have had the chance to directly confront him about his comments on working with segregationist senators and his record on busing. This was one of the most important moments in the entire race so far — it damaged Biden, the longtime frontrunner, while propelling Harris from a distant fourth place to a tie for second.

Meanwhile, the host of other candidates in the race will have even more immediate concerns — because this debate might very well be their last chance.

That’s because the standards for making September’s third debate are significantly tougher. First, candidates have to hit 2 percent or more in at least four polls between June 28 and August 28. Then, they also need to have 130,000 unique donors. Rather than 20 candidates making the cut next time, then, there could be 10 or even fewer. So for most of the field, CNN’s two-night event could be their final opportunity to make their case to a national audience. The pressure, then, will be on.