Key goal for Texans Julián Castro and Beto O'Rourke in Tuesday's debate: Make the next one

The two Democratic presidential candidates from Texas are set to appear Tuesday evening in what threatens to be their last debate, a high-stakes opportunity to propel their campaigns out of the lower tier and prove they deserve their spots onstage.

Julián Castro and Beto O'Rourke are among 12 candidates who will take the stage at 7 p.m. at Otterbein University in Westerville, Ohio, a suburb of Columbus. Hosted by CNN and The New York Times, it is the fourth debate of the primary, and the last one before qualification requirements go up again, potentially leaving the Texans on the sidelines.

In the short term, though, both Texans are being closely watched for their potential collisions with other candidates Tuesday evening. O'Rourke, the former El Paso congressman, is heading into the debate on the heels of his latest clash with South Bend, Indiana, Mayor Pete Buttigieg, while Castro's reputation precedes him after he stood out in the first three debates for his unflinching interrogations of some rivals.

"Some folks have thought that I've been somewhat assertive on the debate stage," Castro said late last month at The Texas Tribune Festival in Austin. "I can tell you that whoever's on the debate stage [in the general election] ... Donald Trump is not gonna be nice."

Still, the debates have proven to be somewhat frustrating experiences for the Texans. Both have had standout moments and enjoyed some fundraising success afterward. But neither has received a discernible boost in the polls as a result.

The latest debate falls on the last day for candidates to report their third-quarter fundraising to the Federal Election Commission. Four days ago, O'Rourke announced he raised $4.5 million over the period, while Castro has not released his numbers yet but offered other fundraising details over the weekend that indicated he took in at least $3.2 million.

Both hauls are improvements over the Texans' second-quarter fundraising but still far behind many of their competitors, especially those that will share the stage with them Tuesday.

The 12-candidate lineup is the biggest for a single night yet, and opportunities abound for conflict. For O'Rourke, that may mean a direct confrontation with Buttigieg, who he has traded barbs with in a series of media appearances and tweets over recent weeks.

The two tangled anew Monday over O'Rourke's crusade for a mandatory buyback program for assault weapons. Buttigieg has suggested the idea plays into Republicans' hands, and O'Rourke has countered that Buttigieg is being too cautious and calculating.

"I get it," Buttigieg said in a Snapchat interview published Monday morning. "He needs to pick a fight in order to stay relevant, but this is about a difference on policy."

O'Rourke shot back on Twitter: "[Buttigieg] can say whatever he wants, but guns kill 40,000 people each year. Those people deserve action. I’ll be fighting for them."

O'Rourke has also faced scrutiny in recent days for saying that religious institutions that oppose gay marriage should lose their tax-exempt status. His campaign later walked back the position, saying O'Rourke was referring to institutions that discriminate, but that did not stop at least two rivals, Buttigieg and Elizabeth Warren, from plainly expressing their disagreement, not to mention an avalanche of GOP criticism.

Castro has not been at the center of as much controversy in recent days, though his aggressive debate style is well known at this point. During the last debate, his questioning of Joe Biden's memory hit on a sensitive subject — the former vice president's mental acuity — that was one of the more dramatic storylines to come out of the event.

Beyond the Ohio debate, though, both Texans are staring down the possibility that they do not qualify for the next one, which is scheduled for Nov. 20 in Georgia. Both candidates have the 165,000 donors required for that debate, according to their campaigns, but neither is close to satisfying the most realistic polling requirement for them: 3% in four national or early voting state polls. Castro has none of the qualifying surveys, while O'Rourke has one.

They have until Nov. 13 to hit the threshold, though neither has been on a promising trajectory lately.

Faced with the November cutoff, Castro has taken a somewhat alarmist approach, sending out a fundraising email late last month warning it would be the "end of my campaign" if he did not qualify for the November debate. Meanwhile, a confident O'Rourke and his campaign have sought to reassure backers not to sweat the November cutoff.

"There is a lot of things to be worried about in the world, and qualifying for the debates is not something that you need to carry on your shoulders," O'Rourke campaign manager Jen O'Malley Dillion said in a recent weekly update for supporters, responding to someone asking how worried they should be about making it on the November debate stage. "Don't worry — we got this one."

Failure to qualify for the November debate could force a fresh round of speculation about the political futures of Castro and O'Rourke. The filing deadline for the Texas primary is just a few weeks later — Dec. 9 — and while both Texans have insisted they will not return home to run for U.S. Senate, the timeline could create a new urgency among their supporters.

A day before the debate, Castro projected the image of a candidate not going anywhere, unveiling 58 endorsements, including at least 14 from Texas. One of them, former El Paso state Rep. Norma Chávez, gave a potential preview of the Ohio debate in explaining her support for Castro.

“Julián is not a lightweight," she told Politico. "He can deliver a power punch and take one."