After two whirlwind presidential primary debates, the number of candidates who qualify for the next meeting of Democratic White House contenders in September is set to narrow significantly.

The Democratic National Committee (DNC) has set stricter thresholds for the third debate, slated to be held on Sept. 12 and 13 in Houston and broadcast on ABC and Univision.

So far 10 candidates have appeared to make it to the stage, while former hedge fund manager Tom Steyer Tom SteyerTV ads favored Biden 2-1 in past month Inslee calls Biden climate plan 'perfect for the moment' OVERNIGHT ENERGY: Trump administration finalizes plan to open up Alaska wildlife refuge to drilling | California finalizes fuel efficiency deal with five automakers, undercutting Trump | Democrats use vulnerable GOP senators to get rare win on environment MORE is just one poll away from qualification. If 10 or fewer candidates qualify, the debate will be held for one night only.

To qualify, candidates need to have at least 130,000 unique donors and at least 2 percent support in four DNC-recognized polls by Aug. 28.

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The criteria are tighter than for the first two debates, which allowed candidates to garner at least 65,000 unique donors or hit at least 1 percent support in three polls.

Twenty candidates qualified for the June and the July debates, which were spread out over four nights.

Making the September stage has therefore become a do-or-die moment for candidates: failure to make it will raise the prospect of stalling in the polls and of fundraising drying up, a usual death knell for campaigns.

Candidates who meet the September requirements will also qualify for the October debate, which use the same criteria.

Some 2020 contenders could fail to make the stage in September but still make it the following month given the extra time they would have to meet the thresholds.

Here’s a list of who’s earned a spot on the September stage so far:

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MADE IT

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Biden has maintained his status as the primary field’s frontrunner with a commanding lead in most polls and strong fundraising numbers.

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Booker has snagged a spot though he's yet to break into the top 5 in national and statewide polls. He ranked sixth in fundraising for the second quarter after collecting $4.5 million.

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Buttigieg, a political unknown just months ago, has had an unexpectedly swift rise in the presidential race and was the biggest fundraiser among 2020 Democrats with $24.8 million.

Former Housing and Urban Development Secretary Julián Castro

Castro has surpassed the 130,000 individual donors threshold and hit 2 percent in a fourth qualifying poll with just days to go before the Aug. 28 deadline.

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After failing to gain much traction earlier this year, Harris catapulted herself up the polls following a confrontation with Biden over racial busing in the first debate in June.

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Klobuchar said in an email she had met the donor threshold after earlier meeting the polling requirement. The senator has failed to gain much traction against higher-profile opponents.

Former Rep. Beto O’Rourke (D-Texas)

O'Rourke's campaign is widely seen as having fizzled despite the hype that surrounded him, but still enjoys name recognition from his near-win in the 2018 Senate race in Texas.

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Sanders has consistently polled in the top tier of most surveys as he pushes his progressive appeal with several liberal policies like “Medicare for All” and calls for a “political revolution.”

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After a slow campaign rollout, Warren has seen her support steadily rise with her “I have a plan for that” playbook of unveiling a slew of detailed policy proposals.

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Yang hit the polling threshold at the beginning of August, becoming the ninth Democrat to qualify for the debate stage. He had previously quarreled with the DNC after it said it would only count one of two polls he had initially intended to submit for qualification since they had the same sponsor.

MAY MAKE IT

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Gabbard's campaign announced it has reached the donor threshold to appear at the primary debate in September and has hit 2 percent in two polls.

Sen. Kirsten Gillibrand (D-N.Y.)

Gillibrand told The Washington Post on Aug. 19 that she's accumulated “just over 110,000” donors. The Post also noted she has one poll that meets the 2 percent requirement, leaving her three short.

Activist Tom Steyer

Steyer's campaign announced he had hit the individual donors threshold in mid-August. He has already reached 2 percent in three qualifying polls, needing just one more to make the debate stage.

Author Marianne Williamson

The self-help author has met the individual donor requirement but does not yet have any qualifying poll.