The third Democratic debate will treat viewers to a spectacle unseen this cycle — all of the qualifying candidates debating on the same stage, on the same night.

When is the next Democratic debate?

Date: Thursday, Sept. 12

Time: 8 to 11 p.m. Eastern. (That’s right, this debate will be three hours long.)

Where: Texas Southern University, a historically black university, in Houston

Why is there only one night this time? Because the Democratic National Committee doubled the polling and donor requirements to make this stage, and so only 10 candidates qualified (compared with the 20 who qualified for the first two debates). Some presidential candidates, such as Sen. Kirsten Gillibrand (D-N.Y.), dropped out after not making this debate.

The field could be split up again into two nights at the next debate in October. The qualifications will remain the same, and an 11th candidate, billionaire Tom Steyer, said he’s qualified for that debate, which would split the debate stage in two.

Who’s in the debate? The highest-polling candidates will stand in the middle of the stage.

Klobuchar

Booker

Buttigieg

Sanders

Biden

Warren

Harris

Yang

O’Rourke

Castro

Klobuchar

Booker

Buttigieg

Sanders

Biden

Castro

Warren

Harris

Yang

O’Rourke

Klobuchar

Booker

Buttigieg

Sanders

Biden

Warren

Harris

Yang

O’Rourke

Castro

Klobuchar

Booker

Buttigieg

Sanders

Biden

Warren

Harris

Yang

O’Rourke

Castro

Who are the moderators? ABC News chief anchor George Stephanopoulos, “World News Tonight” anchor David Muir, ABC News correspondent Linsey Davis and Univision anchor Jorge Ramos.

What should I watch for? This will be the first time that two leaders in the polls, former vice president Joe Biden and Sen. Elizabeth Warren (D-Mass.) will be on the same stage. If anyone has the ability to use debates to knock Biden off his stable position at the top of the polling, it could be her. Biden has given lackluster-to-mediocre debate performances; Warren has typically been strong in hers. Also, do Warren and Sen. Bernie Sanders (I-Vt.), who are splitting the liberal vote in the party, end their truce and attack each other?

How can I watch? Turn on ABC or stream on ABCNews.com. A Spanish translation will also air on Univision.

How did we end up with these 10 candidates?

To qualify for this debate, candidates had to register at least 2 percent in four of the 21 qualifying polls and earn donations from at least 130,000 individuals by Wednesday, Aug. 28.

The debate would have continued the next night only if more than 10 candidates qualified. Exactly 10 candidates made the cut.

Second debate

Third debate

Biden

Biden

Booker

Booker

Buttigieg

Buttigieg

Castro

Castro

Harris

Harris

Klobuchar

Klobuchar

O’Rourke

O’Rourke

Sanders

Sanders

Warren

Warren

Yang

Yang

Bennet

Bennet

de Blasio

de Blasio

Delaney

Delaney

Gabbard

Gabbard

Gillibrand

Gillibrand

Hickenlooper

Hickenlooper

Inslee

Inslee

Dropped

out

Ryan

Ryan

Williamson

Williamson

Swalwell

Swalwell

Bullock

Bullock

Messam

Messam

Moulton

Moulton

Sestak

Sestak

Steyer

Steyer

Requirements to qualify

1% in 3 polls

2% in 4 polls

and

or

65,000 donors

130,000 donors

First debate

Second debate

Third debate

Biden

Biden

Biden

Booker

Booker

Booker

Buttigieg

Buttigieg

Buttigieg

Castro

Castro

Castro

Harris

Harris

Harris

Klobuchar

Klobuchar

Klobuchar

O’Rourke

O’Rourke

O’Rourke

Sanders

Sanders

Sanders

Warren

Warren

Warren

Yang

Yang

Yang

Bennet

Bennet

Bennet

de Blasio

de Blasio

de Blasio

Delaney

Delaney

Delaney

Gabbard

Gabbard

Gabbard

Gillibrand

Gillibrand

Gillibrand

Hickenlooper

Hickenlooper

Hickenlooper

Inslee

Inslee

Inslee

Dropped

out

Ryan

Ryan

Ryan

Williamson

Williamson

Williamson

Swalwell

Swalwell

Swalwell

Bullock

Bullock

Bullock

Messam

Messam

Messam

Moulton

Moulton

Moulton

Sestak

Sestak

Sestak

Steyer

Steyer

Requirements to qualify

1% in 3 polls

1% in 3 polls

2% in 4 polls

and

or

or

65,000 donors

65,000 donors

130,000 donors

First debate

Second debate

Third debate

Biden

Biden

Biden

Booker

Booker

Booker

Buttigieg

Buttigieg

Buttigieg

Castro

Castro

Castro

Harris

Harris

Harris

Klobuchar

Klobuchar

Klobuchar

O’Rourke

O’Rourke

O’Rourke

Sanders

Sanders

Sanders

Warren

Warren

Warren

Yang

Yang

Yang

Bennet

Bennet

Bennet

de Blasio

de Blasio

de Blasio

Delaney

Delaney

Delaney

Gabbard

Gabbard

Gabbard

Gillibrand

Gillibrand

Gillibrand

Hickenlooper

Hickenlooper

Hickenlooper

Inslee

Inslee

Inslee

Ryan

Ryan

Ryan

Dropped

out

Williamson

Williamson

Williamson

Swalwell

Swalwell

Swalwell

Bullock

Bullock

Bullock

Messam

Messam

Messam

Moulton

Moulton

Moulton

Sestak

Sestak

Sestak

Steyer

Steyer

Requirements to qualify

1% in 3 polls

1% in 3 polls

2% in 4 polls

and

or

or

65,000 donors

65,000 donors

130,000 donors

The more stringent rules that the Democratic National Committee laid out for the third debate were an attempt to narrow the historically large field. Five candidates dropped out of the race in July and August: Rep. Eric Swalwell (D-Calif.), former Colorado governor John Hickenlooper, Washington Gov. Jay Inslee, Rep. Seth Moulton (D-Mass.) and Sen. Kirsten Gillibrand (D-N.Y.). But 20 remain in the race.

Candidates on the bubble have missed their chance this round. In two final qualifying polls released Aug. 28, no candidate earned more than 2 percent who has not already qualified for the debate.

On the bubble

Candidates who have polled at or above 2 percent since June 28 but not frequently enough to qualify

IA

State poll

National poll

CANDIDATE

QUALIFYING POLLS

IA

IA

SC

Tom Steyer

Needed 1 more

NH

Tulsi Gabbard

Needed 2 more

Marianne Williamson

Needed 3 more

On the bubble

Candidates who have polled at or above 2 percent since June 28 but not frequently enough to qualify

State poll

National poll

IA

CANDIDATE

QUALIFYING POLLS

IA

SC

IA

Tom Steyer

Needed 1 more

NH

Tulsi Gabbard

Needed 2 more

Marianne Williamson

Needed 3 more

On the bubble

Candidates who have polled at or above 2 percent since June 28 but not frequently

enough to qualify

State poll

National poll

IA

CANDIDATE

QUALIFYING POLLS

Needed 1 more

IA

SC

IA

Tom Steyer

Needed 2 more

NH

Tulsi Gabbard

Marianne Williamson

Needed 3 more

The fourth Democratic debate in October has the same polling and donor requirements. Tom Steyer collected another qualifying poll in September, so he’ll have a spot on stage in October. Rep. Tulsi Gabbard (D-Hawaii) and Marianne Williamson have enough unique donors but each needs a few more qualifying polls to make the cut.

The seven remaining candidates have not hit 2 percent in any qualifying polls or reached the 130,000 unique donor threshold.

Reaching the donor threshold has been easier for most candidates than increasing their standing in polls. All of the 13 candidates who’ve had at least one qualifying poll have already reached the donor threshold.

Steyer reached the threshold after massively outspending all other candidates on Facebook and Google advertisements in the past month, prompting criticism from the field that he is trying to buy his way to the debate stage. He has spent more than $1.3 million on debate-related Facebook ads, according to Bully Pulpit Interactive.

Tom Steyer

Kirsten Gillibrand

Facebook ad

Email to supporters

Tulsi Gabbard

Email to supporters

Tom Steyer

Kirsten Gillibrand

Facebook ad

Email to supporters

Tulsi Gabbard

Email to supporters

Tom Steyer

Tulsi Gabbard

Kirsten Gillibrand

Facebook ad

Email to supporters

Email to supporters

Before Gillibrand dropped out, she spent nearly $600,000 on Facebook ads specifically about debates — more than any other candidate besides Steyer. Gabbard asked supporters in an email to sign up for YouGov and answer calls from unknown numbers in an attempt to reach 2 percent in qualifying polls.

A less publicized DNC rule required each of a candidates’ four polls to come from different pollsters, or from different geographic areas. This caused a minor blowup in July, when entrepreneur Andrew Yang announced he had qualified for the debate, only to be told by the DNC that he could not count both of two national polls conducted (in part) by NBC. He later picked up his fourth poll in Iowa.

POLLED AT LEAST 2%

National poll

Polled less than 2%

IA

State poll

Does not count

Biden

IA

SC

NH

NH

SC

IA

SC

IA

JUNE 28

AUG. 28

Buttigieg

IA

SC

NH

NH

SC

IA

SC

IA

Harris

IA

SC

NH

NH

SC

SC

IA

IA

Sanders

IA

SC

NH

NH

SC

IA

SC

IA

Warren

IA

SC

NH

NH

SC

IA

SC

IA

Booker

IA

SC

NH

SC

IA

SC

O’Rourke

NH

NH

Klobuchar

IA

IA

IA

Yang

IA

Castro

IA

Steyer

SC

IA

IA

Not included in polls

Gabbard

NH

Williamson

POLLED AT LEAST 2%

National poll

Polled less than 2%

State poll

IA

Does not count

Biden

IA

SC

NH

NH

SC

IA

SC

IA

JUNE 28

AUG. 28

Buttigieg

IA

SC

NH

NH

SC

IA

SC

IA

Harris

IA

SC

NH

NH

SC

SC

IA

IA

Sanders

IA

SC

NH

NH

SC

IA

SC

IA

Warren

IA

SC

NH

NH

SC

IA

SC

IA

Booker

IA

SC

NH

SC

IA

SC

O’Rourke

NH

NH

Klobuchar

IA

IA

IA

Yang

IA

Castro

IA

Steyer

SC

IA

IA

Not included in polls

Gabbard

NH

Williamson

POLLED AT LEAST 2%

National poll

Polled less than 2%

State poll

IA

Does not count

JUNE 28

AUG. 28

Biden

IA

SC

NH

NH

SC

IA

SC

IA

Buttigieg

IA

SC

NH

NH

SC

IA

SC

IA

These candidates have polled at 2% or higher in every poll since June 28

Harris

IA

SC

NH

NH

SC

SC

IA

IA

Sanders

IA

SC

NH

NH

SC

IA

SC

IA

Warren

IA

SC

NH

NH

SC

IA

SC

IA

Booker and

O’Rourke’s polling averages are between 2 and 3%

Booker

IA

SC

NH

SC

IA

SC

O’Rourke

NH

NH

Klobuchar

IA

IA

IA

Klobuchar, Yang and Castro have been more successful in national polls than state polls

Yang

IA

Castro

IA

Steyer

SC

IA

IA

Not included in polls

Steyer, Gabbard and Williamson have reached the donor threshold but not the polling threshold

Gabbard

NH

Williamson

POLLED AT LEAST 2%

National poll

Polled less than 2%

State poll

IA

Does not count

JUNE 28

AUG. 28

Biden

IA

SC

NH

NH

SC

IA

SC

IA

Buttigieg

IA

SC

NH

NH

SC

IA

SC

IA

These candidates have polled at 2% or higher in every poll since June 28

Harris

IA

SC

NH

NH

SC

SC

IA

IA

Sanders

IA

SC

NH

NH

SC

IA

SC

IA

Warren

IA

SC

NH

NH

SC

IA

SC

IA

Booker

IA

SC

NH

SC

IA

SC

Booker and O’Rourke’s polling averages are between 2 and 3%

O’Rourke

NH

NH

Klobuchar

IA

IA

IA

Klobuchar, Yang and Castro have been more successful in national polls than state polls

Yang

IA

Castro

IA

Steyer

SC

IA

IA

Not included in polls

Steyer, Gabbard and Williamson have reached the donor threshold but not the polling threshold

Gabbard

NH

Williamson

POLLED AT LEAST 2%

National poll

Polled less than 2%

IA

State poll

Does not count

JUNE 28

AUG. 28

Biden

IA

SC

NH

NH

SC

IA

SC

IA

IA

NH

NH

SC

SC

SC

IA

IA

Buttigieg

These candidates have polled at 2% or higher in every poll since June 28

Harris

IA

SC

NH

SC

SC

NH

IA

IA

Sanders

IA

SC

NH

NH

SC

IA

SC

IA

Warren

IA

SC

NH

NH

SC

IA

SC

IA

Booker

IA

SC

NH

SC

IA

SC

Booker and O’Rourke’s polling averages are between 2 and 3%

O’Rourke

NH

NH

Klobuchar

IA

IA

IA

Klobuchar, Yang and Castro have been more successful in national polls than state polls

Yang

IA

Castro

IA

Steyer

SC

IA

IA

Not included in polls

Steyer, Gabbard and Williamson have reached the donor threshold but not the polling threshold

Gabbard

NH

Williamson

Shelly Tan contributed to this report.

About this report

This analysis is based on rules set by the DNC. Individual donor numbers are reported by the campaigns. Polling totals are based on numbers compiled by Politico. The images of candidate emails and ads are from the Archive of Political Emails and Facebook’s Ad Library.