Julián Castro and Sen. Elizabeth Warren have, at various points in the Democratic presidential primary, acted more as friends than foes.
Brian Powers/The Register/USA TODAY NETWORK via Reuters

When Julián Castro walked off the Miami debate stage in June, his campaign staff felt confident he’d had a successful night. They weren’t the only ones.

U.S. Sen. Elizabeth Warren sent him a text congratulating him on his performance.

For any other sharp-elbowed politicians competing for their party’s nomination, the exchange might have been unusual. But Warren and Castro have, at various points in the primary, acted more as friends than foes.

Perhaps more than any other pair, the two candidates have shared tender moments throughout the presidential race, raising eyebrows across the nation. A photo of the two embracing at the Iowa Steak Fry, tweeted by Warren with a caption calling Castro a friend, racked up 13,000 likes.

Castro, mired at the bottom of most national polls and on the brink of not making the cutoff for the November debate stage, has found an ally in Warren, whose profile continues to climb. It has led to speculation — or palpable hope for fans of both candidates — that Castro might be a leading choice for vice president on a Warren ticket. While Castro previously gave no indication he wanted to throw in the towel early, a recent fundraising email showing his campaign on the ropes has only intensified the scrutiny.

The two make an unlikely pairing. On the one hand is a cerebral, young Hispanic man who is a former Cabinet member and exudes poise bordering on robotic — a “LatinObama,” according to the comedy writers of “Saturday Night Live.” On the other is a white woman, dozens of years his senior, who’s running an upbeat, “I’ve got a plan for that” campaign and isn’t shy about speaking her mind.

Both candidates’ campaigns declined to comment for this story. But those close to Castro’s campaign say the two developed a healthy working relationship when he was U.S. housing secretary under then-President Barack Obama. Warren sat on the Senate Committee on Banking, Housing and Urban Affairs while Castro was at Housing and Urban Development, and he frequently worked with lawmakers overseeing HUD’s budget and programs. Over months of touring the country to court Democratic primary voters, that initial respect developed into genuine camaraderie. It was cemented, in part, by shared progressive ideals and a love for wonky policy proposals.

“Game recognizes game,” said Democratic state Rep. Poncho Nevárez of Eagle Pass, one of Castro’s early supporters.

The affection the two have for each other was nowhere more pronounced than during a May TV interview with MSNBC’s Lawrence O’Donnell, when Warren praised Castro’s comprehensive immigration plan.

“What is the best policy idea that you have heard from one of your competitors in this campaign?” O’Donnell asked Warren as the interview wound down.

“Oh, I think Julián Castro,” she said. “His idea around immigration and about changing how we treat people who come here and who are not documented. I think he’s got some really good ideas around this. I am very interested in his work. I admire it.”

Warren later told The Huffington Post she was joining Castro in calling for the repeal of Section 1325, a key and controversial part of his immigration plan that proposes decriminalizing unauthorized border crossings. When giving her nod of approval, she praised Castro by name and advocated for passing comprehensive immigration reform “that is in line with our values [and] creates a pathway to citizenship for undocumented immigrants.”

The compliment was said to have made an impression on Castro, who despite being the only Latino candidate in the race and the first one to unveil an immigration proposal, had at the time received few plaudits from his other Democratic rivals on his plan.

Castro’s team ran with the momentum, and the San Antonio Democrat responded to Warren’s comments on Twitter. “Thank you, @ewarren, for joining me on this issue,” he said. “We shouldn’t criminalize desperation — it’s time to repeal this terrible law.” (He also previously lauded Warren’s child care plan.)

Last week, Warren again expressed her fondness for Castro — joining him in opposing a measure proposed by the Las Vegas City Council that would criminalize homelessness. On Twitter, Castro’s spokesman, Sawyer Hackett, called Warren “a true class act” for referencing the Texan by name in her statement on the proposal.

“[Warren’s] helping to raise awareness for [Castro], for sure, and she’s helping validate plans he knows are already good,” said Minyon Moore, a political strategist who previously worked for Bill Clinton’s administration. “She’s steeped in policy proposals, so I think the validation is good.”

Politics and self-interest have not encroached on the friendship. Although Castro has clashed with fellow Texan Beto O’Rourke and former Vice President Joe Biden on the debate stage, he has never butted heads in the same way with Warren. Warren hasn’t yet railed against the former housing secretary, either.

Some skeptics have downplayed the relevance of their friendship since Warren and Castro built their brands along similar progressive policy lines.

Plus, Warren isn’t the only candidate Castro has taken a liking to. Rival Cory Booker once led a “Julián” chant at a Nevada rally, a Castro aide told Time. Castro tweeted birthday wishes to Booker on “the big 5-0.” Warren, meanwhile, in a friendship that has since turned combative, initially found an ally in progressive Sen. Bernie Sanders of Vermont.

What stands out about the Warren-Castro alliance is that it has persisted. Warren has firmly established herself as one of the Democratic frontrunners. She doesn’t stand to gain much, if anything, by showering Castro with praise. He, meanwhile, reaps the benefits from an upped name ID and media attention.

As a result, Castro has found himself in a precarious political position: Democratic voters have exalted his message, but if the polls are any indication, they seem to prefer Warren as the person to deliver it.

Although people close to both candidates insist their admiration for one another is effusive, for Castro, befriending the head honcho comes with its own set of advantages.

“It certainly behooves someone in the single digits to befriend someone in the double digits who appears on the ascendancy,” said Colin Strother, a Texas Democratic strategist who once advised both Joaquin and Julián Castro.

It’s not uncommon for former primary rivals to later join a ticket together. Some other notorious odd couples include Democrats John Kerry and John Edwards and, more recently, Obama and Biden.

“It’s interesting to watch,” Strother said of Castro and Warren. “I think that the 70-year-old crowd [of candidates] represents one thing, and the rest of the field represents another. It’s going to be really important for Warren, especially when we start talking about electability and winning in November, to be able to be able to say, ‘I have a young friend. I have a Latino friend. I have a pragmatist friend.’

“Look, at the end of the day, there’s going to be one person who gets the nomination, and he or she is going to build out a ticket and a cabinet and all that that implies,” he said.

Some of the candidates’ biggest fans have backed the duo for a potential ticket.

“I know if [Warren’s] campaign is fortunate enough to get to that place will be weighing a lot of different options, but I can certainly see that as a possibility,” said state Rep. Erin Zwiener, D-Dripping Springs, the first Texas elected official to endorse Warren.

“I’ve said multiple times I think it would be a huge mistake for the Democrats to have an all-male ticket or an all-white ticket,” she said. “[Warren-Castro] has both a woman and a person of color on it. … It also offers up some geographic diversity.”

Moore, meanwhile, said it’s too early to speculate whether Warren will be the presumptive nominee and if her affection toward Castro resembles the type of courtship that happens when a leading candidate is exploring vice presidential contenders.

Candidates, she said, develop a sort of familial bond on the campaign trail. The job requires presidential aspirants to put their lives and families on hold, and the only ones who can truly relate are the dozen or so people campaigning — sometimes actively — against them.

Castro, for his part, might not accept a role as No. 2. Campaign aides insist he’s set on becoming president, despite having less than $700,000 in the bank at the end of the latest fundraising quarter. Rumors also recently surfaced that Warren was courting former Tallahassee Mayor Andrew Gillum, though her campaign quickly shot down the idea.

And it’s not the first time that Castro’s name has been floated as a vice presidential candidate; during Hillary Clinton’s 2016 run, rumors abounded of a Clinton-Castro ticket that never came to be.

Like the political futures of both Castro and Warren, it’s unclear how long the chumminess will last. But for now, spectators seem to be enjoying the shows of friendship and encouragement.

“People like to see that. It seems like we’re pulling each other to opposite ends or we’re pulling against each other, and I think people like to see us in politics or in public life pulling together,” said Nevárez, the Eagle Pass state representative.

“We’re desperately in need of cooperation and seeing cooperation.”