Julián Castro's campaign had been stalled for months. Wednesday's debate gave it new life.

MIAMI – Before Wednesday night, even some longtime Julián Castro fans had been privately wondering if his presidential campaign was effectively over.

In a Democratic field that includes political novices and back-bench U.S. House members, the former San Antonio mayor and Obama cabinet member had become an afterthought.

“He just had been forgotten,” said Moses Mercado, a Democratic lobbyist who is close to a number of Texas members of Congress.

Then came the first debate.

“He needed to do something,” Mercado added. “I’m not sure if I'd been smart enough to say, ‘Go after O’Rourke,’ but it worked. ... In execution, it was brilliant.”

It's a sentiment with which Castro agreed in a news conference Thursday morning.

"Coming into the debate, it was clear that I had to introduce myself to the American people," he said. "There are a lot of voters who didn’t know who I was, what I’d like to do if I’m elected president. I accomplished my goal for the debate."

Castro's campaign is officially jump-started. How long it lasts and how far he can carry this momentum is anyone's guess in this turbulent political moment.

But Castro had been promising for months that his presidential campaign would live or die based on his performance at the first presidential debate.

For now, at least, "Castro for president" will live to fight another day.

Castro's biggest problem has been a Democratic field so sprawling that only top-tier candidates have been able to earn significant attention. His second-biggest problem has been Beto O'Rourke, the former congressman from El Paso who saw his national profile rise last year via a spirited campaign against U.S. Sen. Ted Cruz.

Democrats are making it up as they go along in getting a handle on the 23-candidate field. To keep the first debates manageable, they split the field into two nights and excluded a handful of contenders. By chance, Castro landed on the first stage with the Texan who has outshone him for over two years — O'Rourke. And it was O'Rourke he went after.

Sparring over whether to repeal a federal law that criminalizes improper border crossings, Castro interrupted his fellow Texan and unleashed on him:

"You said recently that the reason you didn't want to repeal Section 1325 was because you were concerned about human trafficking and drug trafficking," Castro said to O'Rourke. "But let me tell you what: Section 18, title 18 of the U.S. code, title 21 and title 22, already cover human trafficking."

As the two men talked over one another, Castro got out what would turn out to be the line of the night: "If you did your homework on this issue, you would know that we should repeal this section."

O'Rourke did little to further inflame the tensions Thursday morning as he visited the controversial migrant detention center in Homestead, south of Miami. Fielding questions about Castro from a mob of reporters, O'Rourke continued to say he disagreed with Castro's criticism and maintained that they both have the same immigration goals but that Castro may not understand how O'Rourke wants to achieve them.

Yet O'Rourke also moved quickly to try to flatten Castro's momentum, announcing Thursday morning that he will hold a campaign event Friday evening in Austin. The event is set for one hour before a planned Castro meet-and-greet just blocks away.

O'Rourke's campaign did not stop there. In a media advisory detailing the Austin stop, the campaign noted that in a recent Texas poll, "Beto held a three-point lead over Vice President Joe Biden and a twenty-five point lead over fellow Texan, Julián Castro."

"I did my homework"

For over a decade, Castro was the next big thing in Democratic politics. While mayor of San Antonio, President Barack Obama selected him to deliver the 2012 Democratic National Convention keynote speech — the platform that launched Obama and, in 1988, future Texas Gov. Ann Richards to political stardom.

But that speech — and Castro’s municipal and federal service — were mostly forgotten when contrasted against the flash of the crowded Democratic field.

It did not help that Castro launched his bid in January, when many were more focused on whether his fellow Texan — O’Rourke — was going to join the race, too. Castro could not even credibly claim to be the dominant Democrat in his own backyard.

Yet Castro has taken several steps to distinguish himself in a crowded field. He made Puerto Rico the first place he visited after officially kicking off his campaign, and he has since become the first 2020 candidate to visit Flint, Michigan, the site of an ongoing water crisis. He was the first 2020 Democrat to release a detailed immigration plan, and only O'Rourke has since joined Castro in putting out such a platform. And he was the first 2020 contender to say impeachment proceedings should begin against President Donald Trump, beating U.S. Sen. Elizabeth Warren of Massachusetts by a matter of hours.

Still, the national media has not always given Castro the attention — or credit — for the distinct moves, a source of mounting frustration within his campaign in the run-up to Wednesday night. After the debate, Castro was not shy about airing the grievances.

“The media have been paying attention only to certain candidates so far,” Castro told reporters as he navigated a post-debate scrum late Wednesday night. “I think that’s going to change after tonight.”

Heading into this week, speculation had grown that Castro's campaign was on its last legs. His fundraising was in the tank, and worsening the situation, Castro's twin brother, U.S. Rep. Joaquin Castro, frustrated Texas Democrats by declining to run for U.S. Senate after a prolonged deliberation.

But Wednesday night marked a confluence of factors in Castro’s favor. The dimmed star power in the first debate gave him an opportunity to be the center of attention he likely would not have had if he drew a Thursday night debate lot.

Mostly, though, television underscored that Castro was the only Latino major candidate running for president, and he presented himself as an expert on immigration policy. With the misery at the U.S.-Mexican border and in detention centers elsewhere in the country at the forefront of Democratic voters' minds, Castro finally had an opening.

“You have to be prepared. I prepared myself. I did my homework,” he said Thursday morning, another veiled shot at O'Rourke. “And that clearly paid off.”

As the sun came up in South Florida on Thursday morning, the glow was on Warren. She was the highest-polling Democrat on the stage Wednesday night, and pundits widely perceived her as the best-performing candidate.

But that Castro managed to stand out at all was unexpected — and it was news. Nothing helps a lower-tier presidential candidate break through the noise like beating expectations.

Since last night, Castro has found himself at the center of political fascination. It was not just that he pushed himself to the front — but that he did it at O’Rourke’s expense. Intrastate rivalries in presidential contests always make for great drama. Think of the endless speculation around the relationship between former Florida Gov. Jeb Bush and U.S. Sen. Marco Rubio in 2016.

The Castro camp repeatedly stressed that the move was not personal.

“I like him," Castro said of O'Rourke on Thursday morning.

When asked Thursday morning if he had a better shot than O'Rourke at flipping Texas, he did not pause: "Yep, sure."

"I believe that I’m the party’s best shot at getting 29 electoral votes in Florida, the 11 electoral votes in Arizona and 38 electoral votes in my home state of Texas," Castro said. "And that if I am the nominee, we will see unprecedented gains in the Latino vote. That it will go through the roof. And that that will have consequences, positive consequences, for the Democratic Party like you’ve never seen before."

Maintaining momentum

The bigger problem for Castro is that he's only hours away from the next debate. And as much as his back-and-forth with O’Rourke raised eyebrows, the center-stage fight between former Vice President Joe Biden and U.S. Sen. Bernie Sanders of Vermont is the one Democrats are raring for.

So Castro’s moment in the Sunshine State could be fleeting.

The onus is on him is to leverage the attention into a debate slot in September, when the selection process gets more restrictive. Party leaders are anxious for the field to thin. Castro is almost certain to make the cut for the next set of debates in July. But for the third debate, he will need to draw at least 2 percent support in four qualifying polls and the support of 130,000 individual donors.

The latter cause may have been helped Wednesday night. Castro indicated Thursday that his fundraising after the debate had been the best of his campaign so far.

“I showed the American people that I have the right experience to be president. That I have a strong, compelling and positive vision for the future of this country. And that I can hold my own, go toe-to-toe with Donald Trump."

It’s a sentiment Castro has expressed before. It's just that, for the first time, he is being taken seriously.