If the buzz about Julián Castro's vice presidential prospects wasn't deafening before last week, it is now.
Castro's endorsement of Hillary Clinton for president — delivered at a festive rally Thursday in his hometown of San Antonio — breathed more life than ever into the idea that he's her running mate-in-waiting for the Democratic ticket. For supporters of Castro, the U.S. housing secretary and former San Antonio mayor, the event provided the clearest glimpse yet at what a Castro-Clinton pairing could look like — and they loved what they saw.
"When you look at Julián’s incredible rise, how could he not be at the top of the list?" asked Christian Archer, Castro's political chief when he was mayor. "There’s a clear message when you do your first big rally [in Texas] and it’s right here in San Antonio.”
"That looked like a winning American ticket," Archer added, guessing that some who came to the rally were just as excited to see Castro as Clinton.
In a Q&A with the U.S. Hispanic Chamber of Commerce before the rally, Clinton did little to tamp down speculation in what appeared to be her first public comments on the topic. Asked about Castro's vice presidential potential, Clinton said she plans to "really look hard at him for anything because that's how good he is."
Despite the growing frenzy, Democrats acknowledge that it's remarkably early to be talking about Clinton’s choices for vice president, especially with four months until the first primary in a race Clinton vows she is not taking for granted. And Castro's role within the campaign is not yet defined, with the housing secretary expected to step up his involvement as his schedule at HUD permits.
But the early timing has done little to curb months-long rumors that 41-year-old Castro has the inside track for running mate. The buzz follows him to official events for the housing department, where he routinely hushes curious reporters with a boilerplate statement stressing that he is focused on his current job.
In an interview at The Texas Tribune Festival on Sunday, Castro played coy when prodded about his running-mate ambitions, saying he does not “fundamentally believe” he will be tapped for the gig. Plus, he said, “it’s not a given” he would accept the position if offered it.
Texas Democrats are hoping he says yes. Asked in an interview last month about Clinton’s commitment to rebuilding state parties after the Obama years, Texas Democratic Party chairman Gilberto Hinojosa said the best thing to do in Texas was simple: make the "obvious person" — Castro — her running mate. Hinojosa said Castro stands by far the best chance of energizing Hispanic voters, the "largest segment of the community in the state of Texas that is not participating in the electoral process."
"That would have an enormous affect on starting to move our state in much more of a direction of turning it blue,” Hinojosa said, calling the scenario a potentially “perfect storm” when one factors in Clinton’s deep ties to the Hispanic community in Texas. “It could be a game changer.”
Castro boosters often underline their optimism with a simple question: Who else? A few other names have cropped up, including U.S. Sen. Tim Kaine of Virginia, but Castro’s supporters note their guy would bring more diversity to the ticket.
It’s a view shared by Henry Cisneros, the former U.S. housing secretary who made waves in May by saying Castro is Clinton’s sole option for running mate. In an interview Saturday, Cisneros did not go that far, but he made clear he believes Democrats have few other choices for the No. 2 spot on the ticket.
"Our stable is not that large of people who could be vice president,” said Cisneros, another former San Antonio mayor who went on serve in the cabinet. "For one reason or another, the way things worked out, you don't know who exactly that might be, and I think Secretary Castro has got to be at the top of any list, or at least in the top three or four."
In some corners of the Democratic Party, all the talk of Castro's veep chances caused concern about the appearance of inevitability. Castro's twin brother, U.S. Rep. Joaquin Castro of San Antonio, waved off that suggestion while stumping for Clinton in August in Iowa.
"I don't think it's any of that," he told reporters. "The vice presidency has got to be one of the few offices in the country that you don't run for. The nominee of the party picks who their vice president running mate is going to be. So my brother, he understands that's not in his hands. He's not running for that."
It was not lost on Castro's supporters that in his speech at the rally, he imagined watching Fox News call Texas for Clinton on election night — not necessarily from the campaign trail as her running mate, but back home in San Antonio with his daughter. Archer said the line was characteristically clever Castro, and perhaps a "signal to the people that are trying to claim it's inevitable — 'Hey, calm down.'"
Castro is already drawing intense interest from Clinton's Republican critics, including opposition researchers who are trying dig up dirt on him. Moments after he made his endorsement of Clinton official Thursday, the Republican National Committee released a long list of bullet points painting him as an "ethically-challenged politician who is more concerned about self-promotion than actually governing."
"As the vice presidential rumors swirl around Secretary Castro, America Rising will continue holding him accountable for his extreme left-wing views and support of higher taxes," said Amelia Chasse, a spokeswoman for the GOP opposition research shop. "We’ve been building the research out on Secretary Castro for months and are committed to making sure that his record comes under the scrutiny it deserves — and the same applies for any other so-called Democratic rising stars."
As the speculation about vice presidential prospects enters a new stage, Castro's boosters are welcoming the GOP scrutiny as a sign Republicans view him as not only a rising star, but also a serious threat to their electoral hopes.
"I don't blame the Republicans for being scared of Julián. They should be," Archer said. "He's the face of certainly Texas, of certainly the future of America, and I think that scares the shit out of them."