FILE -- The stage for the Democratic presidential debate inside the Gaillard Center in Charleston, S.C., Jan. 17, 2016. The Democratic National Committee is excluding three candidates from the June debates. Some who are expected to be left out, like Gov. Steve Bullock of Montana, are not happy. (Travis Dove/The New York Times)

The Democratic National Committee announced the candidates who qualified for the first debates of the 2020 presidential campaign Thursday, chopping the historically large field of 23 contenders down to the 20 available slots.

Texas Democrats Beto O’Rourke, a former El Paso congressman, and Julián Castro, a former mayor of San Antonio, made the cut.

Gov. Steve Bullock of Montana, Rep. Seth Moulton of Massachusetts and Mayor Wayne Messam of Miramar, Florida, did not qualify, and will be left out of the debates June 26-27 in Miami, according to a news release sent out Thursday night.

The candidates who made the cut did so by registering 1% support in three polls, receiving donations from 65,000 people, or both.

To determine the 10-candidate lineup for each debate, the committee has said it will evenly and randomly divide top-tier candidates across the two nights. NBC News, which is moderating the first debates, will select the lineups Friday.

The June debates will be the first time many Americans see the Democratic field. For candidates outside the top tier, the debates present a chance for a breakout moment — though they will have to fight for airtime with nine other people on the stage each night.

Bullock, who kicked off his campaign May 14, has been outspoken about his displeasure with the party and the methods it used to pare down the field. In emails to donors, he complained vociferously after a poll that would have helped qualify him for the debates was excluded from consideration. And on Thursday, Bullock’s campaign said it had lobbied the DNC for inclusion in the debates one more time, arguing again that the disqualified poll should be counted.

Two other polls released last week gave Bullock a pair of additional chances to meet the threshold. Had he received 1% support in either of those polls, Bullock would have become the 21st candidate to qualify for the June debates, and that would have forced officials to employ tiebreakers to determine which candidate would be excluded.

In anticipation of the bad news expected Thursday, he put out a statement emphasizing, as he has repeatedly over the past few weeks, that he had delayed entering the race in order to work with the Montana Legislature to renew the state’s Medicaid expansion.

“While 20 candidates are on the debate stage in Miami, I will be talking directly to voters about my record of passing progressive priorities in a state Trump won, the importance of winning the places we lost, and how we are going to beat Donald Trump once and for all,” Bullock said.

Moulton has yet to garner 1% of support in any qualifying poll since he began his campaign to become the Democratic nominee in April. Last week, a spokesman for the campaign declined to say how many people had donated.

“I knew that getting in so late that I’d probably miss the first debate,” Moulton said Thursday. “The DNC debates are not going to determine the nominee. The American people are.”

He added, “I recognize I have to play a bit of catch-up, but I don’t have any regrets for getting in late.”

Messam has also struggled to gain attention, having reached the 1% threshold in only one poll. The campaign did not respond to requests for comment last week about its fundraising efforts and Messam’s status in the debates.

The uphill climb toward the nomination is only getting steeper for long shot candidates like Bullock, Moulton and Messam.

About two weeks ago, the Democratic National Committee announced that it would toughen the requirements for participation in the fall debates. To qualify for the party’s third debate, scheduled for mid-September, candidates will have to attract donations from 130,000 individuals and register at least 2% in four state or national polls from a list of approved surveys.

More than half of the sprawling field is at risk of falling short of that threshold, and news of the more stringent rules sent shock waves through the campaigns on the margins. Some of the most vulnerable candidates have argued that the standard forces them to spend time and money recruiting donors, rather than investing in staff or online advertising.

“We set forth the rules early,” Tom Perez, the party chairman, told The Times this week. “We communicated them clearly to everybody. We got no objections when we communicated the rules of participation.”

But that has not stopped some candidates from complaining. Some have maintained that party officials are winnowing the field far too early, or that the mechanics of qualifying for the debates are unfair. Gov. Jay Inslee of Washington has insisted — to little avail — that party officials reserve a debate exclusively for climate change.

“I believe everybody is, in fact, getting a fair shake,” Perez said. “At the end of the day it’s going to be up to voters.”